RTH - experiencing violent truck-wide shudder on accelleration!

RescueU · 06-25-09, 01:06 PM

****I've moved this from wingnutter's original thread****

Folks,

I'm presently dealing with the same thing right now! Had the problem begin suddenly one day heading to the office (highway with rolling hills). Checked out underside and found rear O2 sensor dangling with leaks @ cat gaskets.

Recently, replaced cat gaskets and both oxygen sensors (OEM Denso's). After pulling EFI fuse to reset ECU, she ran like a dream for maybe a week. No shuddering on accelleration (while under load, like heading up hill) as before. Thought I had it licked until....

This past weekend, while on highway, I was about to take an offramp when I saw it was totally backed up. As I pulled back into travel lane going 40-50mph, I see in rearview mirror a car barrelling down on me, so I accellerate (not floored, but strong punch). Maybe 2 secs into accelleration the CEL pops on and the engine shudders, like a misfire, with dramatic loss of power and the shuddering returns just like prior to O2 sensor replacement & ECU reset.

Pulled the code and it was the P0303 - Cylinder #3 misfire.

I cleared the CEL and reset ECU. Next day headed to work, problem returned. So now, as it happened this morning, if I'm doing 60 on the highway (cruise control or manual) and reach an incline grade where the engine needs to shift (while in OD) to 3k rpm that's when the shuddering (aka like rumble strips at a bridge, or the hand of God shaking the whole truck,etc) kicks in. At this point, if I let off the gas it subsides. Switching OD off and dropping down to 50mph buys me some time. But the last large incline (RT267 VA tollroad westbound prior to Huntermill rd exit), now shuddering kicks in and I have to drop it below almost 40mph @ 2500rpm to keep from shuddering, and it feels like power loss is getting worse.

Pulled into gas station (with overhang for cover to cool down) and checked oil. Near the "L" line, which I topped with Mobil 1syn Extended Performance 10W-30. (note: I've been going thru almost a quart of oil per tank; no leaks on ground or elsewhere detected; exhaust not smoky - WTF?) Tranny fluid is fine. At no time in any events have engine pressure or water temp gauges been anything but normal.

I've read every thread I can find on this, and I have to believe the issue lies with the engine and not the tranny. Largely due to the fact that after cat leak, O2 sensors and ECU reset were done, the problem vanished. And I pushed her up to 70 mph with load and nothing, until I had to really punch the gas quickly.

I have done a visual check on the intake hose but not pulled it for a more thorough inspection - nothing obvious seen so far. New OEM plugs, Nology Hotwires and Cap/rotor were replaced last Summer/Fall (I've gotta start righting that down!). Maybe only 5k mi put on her since. Will pull all and check at first availabilty. (need to get to the office). And no obvious heat damage visible to harness near EGR and all #0 hoses are intact. (See attached pic of EGR with discoloration in front - I suspect it's original factory)

I've seen a bunch of thread. Like wingnutters where all efforts were made to diagnose the issue, but I don't recall seeing many post-mortem reports after root-cause was actually found with details on the fix that mitigated the issue (with exception of wire harness burned by EGR).

Can someone shine some light on what's been collectively learned on this problem. I get the sense many others are experiencing this (at one point or another)

Thanks!! And as always, very grateful I can turn to thus community for help. Truly an invaluable collection of experience...and cast of characters.

SeanAndHis80 · 06-25-09, 01:14 PM

If you do not think it can be the ignition wires - the only thing left would be the injector wires. I would at the very least trace the injector harness and see if it is brittle and might have some insulation issues. Running along the top of the engine it sees its fair share of heat.

Grench · 06-25-09, 01:23 PM

Clogged cat that gets worse when the engine is hot and under stress?

RescueU · 06-25-09, 01:50 PM

Quote:

Originally Posted by SeanAndHis80

If you do not think it can be the ignition wires - the only thing left would be the injector wires. I would at the very least trace the injector harness and see if it is brittle and might have some insulation issues. Running along the top of the engine it sees its fair share of heat.

Sean, I got up under the hood (always fun to do in business attire

) and checked that harness... boy is it close to the EGR pipe!! Nice design.

Anyway, i didn't see any evidence that the shielding had been compromised, but then that really doesn't speak to what's happening on the inside, does it.

How can one get that harness out away from the EGR and firewall to give it a good inspection? Does it require the 2 EGR components to be removed? (can't recall, how many

is swapping out the EGR components?)

I can't picture the injector harness right now.

I'll look it up and inspect it. Thanks for the ideas.

Quote:

Originally Posted by Grench

Clogged cat that gets worse when the engine is hot and under stress?

Grench, you know.. .that's a good thought.

I'm trying to reconcile in my head why after replacing the O2 sensors and ECU reset, she ran without issue for a few days. It took that acceleration stressed event to pop the CEL and now the original problem is back. If clogged, I'd have thought the cats would've still maintained this condition after the 02 sensor replacements. Needless to say, it would not hurt one bit to swap out those 2 nasty OEM pieces for a new spun Magnaflow.

BTW, after i had it in the shade and cooled down for a few hours, I removed the air intake tube and gave it a full inspection... fully intact with no cracks. The TRD airfilter is plenty translucent also.

I pulled the front spark plug wires cover off and inspected all cables at the cap and at plugs #1-4. All seated well with no indications of damage.

Only thing I can think of next is to drop the cash for new rotor, cap, plugs and wires and swap it all out. Seems like 5k mi is a bit short for those items, but maybe i'm wrong.

SeanAndHis80 · 06-25-09, 02:19 PM

Quote:

Originally Posted by RescueU

Only thing I can think of next is to drop the cash for new rotor, cap, plugs and wires and swap it all out. Seems like 5k mi is a bit short for those items, but maybe i'm wrong.

That would be a very short life for those - they should make 60K easily. At least for OEM.

little_joe · 06-25-09, 02:33 PM

Pull the plugs and "read" them. The oil consumption and #3 misfire may well be related - oil getting past the rings?

SeanAndHis80 · 06-25-09, 02:39 PM

Quote:

Originally Posted by little_joe

Pull the plugs and "read" them. The oil consumption and #3 misfire may well be related - oil getting past the rings?

Good call - I would guess valve seals could do this too. "a quart of oil per tank" is a lot. I would say that is roughly 5x faster than I burn it.

RescueU · 06-25-09, 03:33 PM

Thing is, I've been trying to figure out where the frack the oil is going? It ain't on the ground, and i don't have smoke billowing out the tail pipe.

RescueU · 06-25-09, 04:12 PM

Driving home from office...

1mi away @ light - idle is ~4600rpm
3 miles - as I'm halfway up first long incline, shuddering begins @ 50mph-2k rpm and need to turn off OD
5 miles. - next incline w/o OD, hit shuddering @ 40mph-2200 rpm.
7 miles - accellerating up slight hill from stop light, shuddering begins after shifts into 2nd gear reaching ~40 mph - 2k rpm.
9 miles - Can reach up to 50mph - 3k rpm w/o shudder on flat/level stretch of road.

11 miles - Reached home. Idle in park & neutral is -6200rpm; ~6000 rpm in drive w/ foot on brake.

SeanAndHis80 · 06-25-09, 04:15 PM

>Pulled the code and it was the P0303 - Cylinder #3 misfire.

Pull #3 and tell us what you see.

RescueU · 06-26-09, 01:57 PM

Sorry to keep you folks waiting.

I worked all night till 6:30am, got up @ 11:30am and just finished now. Gonna spend some time with the kids for a bit and then will crack open the hood and pull #3 sparkplug.

Cheers!

racerdave · 06-26-09, 02:45 PM

Quote:

Originally Posted by RescueU

Sean, I got up under the hood (always fun to do in business attire

) and checked that harness... boy is it close to the EGR pipe!! Nice design.

Anyway, i didn't see any evidence that the shielding had been compromised, but then that really doesn't speak to what's happening on the inside, does it.

How can one get that harness out away from the EGR and firewall to give it a good inspection? Does it require the 2 EGR components to be removed? (can't recall, how many

is swapping out the EGR components?)

I can't picture the injector harness right now.

I'll look it up and inspect it. Thanks for the ideas.

With the engine running flex the section of the harness behind the ERG (may have to wear gloves) and see if you can make it misfire. Also, after driving are the cats way hot? hotter than normal? If you drive with the engine misfiring you might be dumping raw fuel into the exhaust where it will be burned in the cats, not good unless want new ones.

I had a similar issue last fall and it was an issue with the harness. I had to pull it apart and repair 2 wires. I couldn't see the damage until the harness was pulled apart. I could make it misfire by flexing the harness.

See here for more info - http://forum.ih8mud.com/80-series-te...ning-80-a.html

RescueU · 06-26-09, 04:03 PM

Racerdave, that's some good info. I got up under the hood and got my fingers on the wrapped harness behind the EGR (yeah, gloves not optional)

the harness wrap is still pliable, and I moved it about here and there...no misfires produced.

Gonna pull the plugs and take a look.

Makes me ask, when replacing the plugs, are there other parts that should be replaced also while into that PM? Like gaskets, boots, etc that's down there in the plug holes.

Thanks.

RescueU · 06-27-09, 06:20 AM

Finally getting the chance to get under the hood this morning. I picked up a set of NGK platinum plugs that I figured I'd swap out while i'm in there. I believe these come spec with .032" gap already set, but I was wondering if anyone has had to re-gap them for any reason.

Thanks.

Kernal · 06-27-09, 07:00 AM

A loose spark plug boot (or corrosion, etc) on number 3 spark plug??

alia176 · 06-27-09, 07:30 AM

Quote:

Originally Posted by RescueU

Driving home from office...

1mi away @ light - idle is ~4600rpm
3 miles - as I'm halfway up first long incline, shuddering begins @ 50mph-2k rpm and need to turn off OD
5 miles. - next incline w/o OD, hit shuddering @ 40mph-2200 rpm.
7 miles - accellerating up slight hill from stop light, shuddering begins after shifts into 2nd gear reaching ~40 mph - 2k rpm.
9 miles - Can reach up to 50mph - 3k rpm w/o shudder on flat/level stretch of road.

11 miles - Reached home. Idle in park & neutral is -6200rpm; ~6000 rpm in drive w/ foot on brake.

Some clues that I'm honing in on are in bold

Try these easy tests please and report back:

power break test: left foot firmly on the brake and right foot pushing down on the gas pedal to 2,000 + rpm. Tell us if you can recreate this issue.

Same test but try to drive up a sidewalk so that the engine has to work real hard. You'll be driving head on (perpendicular) to the sidewalk, assuming your sidewalk has a nice sharp edge and is fairly tall, 6" or higher.

Shift Tcase into "low" and then try the same test as above. Do the sidewalk test again.

If the issue returns during any of these three tests, then the engine torque (twisting) is messing with your ECU harness that goes right by the EGR pipe.

RescueU · 06-27-09, 01:09 PM

Quote:

Originally Posted by SeanAndHis80

>Pulled the code and it was the P0303 - Cylinder #3 misfire.

Pull #3 and tell us what you see.

Here you go: Cylinder #3's plug

Tenzig Norgay · 06-27-09, 01:35 PM

I would say pretty nasty, is that caused by oil getting past the rings and fouling it out? Or could a bad plug cause misfire/leaking? I say put the new plug in, take it for a test ride back up an incline and stomp on it.

RescueU · 06-27-09, 01:44 PM

I did all of Alia's tests he advised earlier this morning and I think once or twice I felt a hiccup (misfire?) as it reached 1800 rpm, but that's it.

Never could get the rpms above 2000. No matter if in D, D (no OD), 2 or 1. In fact I ran enough tests to the point where the light went off on the dash for A/T Temperature! Note to self, don't prolong tests or do 15 of them when 2 or 3 will do!

SeanAndHis80 · 06-27-09, 02:18 PM

That looks oil-fouled to me. Show another plug for comparison - it may be one cylinder or it may be all of them with #3 reporting first. Get a new set and swap them. They will take a little while to foul again but the truck should run well in the meantime. If this is the case - you need to track down the source of the oil leak and it is probably time for head gasket PM.

Michael Hanson · 06-27-09, 02:33 PM

Oil has to go somewhere it doesnt disappear.My guess your burning it,do a compression test and a vacuum test this will tell you.The plug looks worn and the gap not right.When did youlast change them ? The EGR looks like .......when has it been last changed? 2 cents MIke

RescueU · 06-27-09, 04:38 PM

I only had time to swap out #3's plug with a new NGK Platinum. Tomorrow I'll finish replacing the other five.

I asked my neighbor to take a look @ the plug. For reference, he's a long time wrencher of both SUV's and race cars. The stuff on the threads is anti-seize I believe. So with the whitish cover over the plugs element, the consensus offered was that the plug showed high combustion, possibly due to lean mixture. Supporting info to this theory is the fact that for sometime I had a leak at my cats and the second O2 sensor was found loose and banging around (due to the nuts dissolving from rust).

I'll post up photos of the other 5 plugs in the morning.

RescueU · 06-28-09, 11:49 AM

I'm back at it again. Looks like this light rain will slip by quickly. Really glad I invested in a decent 10x10 pop-up tent. Worth it's weight in gold.

Well I've finished inspecting and cleaning the inside of the distributor's rotor & cap. I should have just picked up a new set the other day. The rotor was carbon encrusted pretty well, with slight grooves worn into the top and bottom side. I cleaned it off with a combo of file and circuit cleaner to get me thru the moment.

Inside the distributor cap, the points were covered with a whitish carbon-type build up on the flat surface. I cleaned those off as well. I'll attach pics.

I did a resistance test on the #3 high-tension cords (yes, I'm RTFM'g) and registered only 0.8kΩ (max allowed is 25kΩ). So either i've fubar'd the test, or there's no issue with the cord.

Going to move along now to test the other cords and pull the other plugs. Will report back shortly. Hoping the rain does give way.

Again, anyone in DC area wanting to stop by, just give me a ring.

Cheers.

RescueU · 06-28-09, 11:57 AM

Here's what the the rotor looked like when I got done removing the carbon buildup.

SeanAndHis80 · 06-28-09, 01:37 PM

Hey - that looks like excessive wear and the HT lead resistance value is way away from what the stock leads produce. I would get a set of OEM wires. I do not know about Nology Hotwires firsthand - but have driven my OEM wires over 60K miles now. ...just my 02

RescueU · 06-28-09, 01:41 PM

Well, they're all out. Attached photos show them all.

In particular are 2 shots of #6. That plug loosened with relatively little torque compared to the others. Looks like it's got oil all over the element.

Is there anything else I should do while I have all of them out, or should i just get the new plugs in there and see how she does?

BTW, I checked all the plug tubes and they were all clean.

This i fear does not bode well.

SeanAndHis80 · 06-28-09, 02:01 PM

No it does not. #6 would make me suspect head gasket as that seems to be the #1 place they go. Like I said earlier - you can put new plugs in and they should run fine for a little while and then the symptoms will return. A leakdown test would be best but I don't think the result will surprise you.

RescueU · 06-28-09, 02:31 PM

From doing some reading in the forums, it appears that i might be looking at a valve stem seal leak, which could explain the large amount of oil being consumed.

I haven't yet found the details on what equipment is required and the procedure for doing a leak down test.

So... has anyone else that's gone thru this "shuddering" problem ended up with finding an oil-fouled spark plug?

RescueU · 06-28-09, 05:39 PM

Well, i ran down town to Advance Auto to see if they had a compression test kit so i could try a leak down test.

What I found was this: Actron Compression Test Kit - CP7827

I got back and after scouring the FAQ and Forum Search, I found one article that had a picture of a leak down test kit someone had gotten from Summit Racing, along with a pretty darn good description of how to use it. (BTW, why don't we have a FAQ on compression/leak down test procedures...or did I just miss it?)

Suffice to say, I'm not even going to open the package tonight. I've been at this stuff most of the day and just want to get it all back together again. Let's first see how the new plugs work.

I also grabbed a new rotor plug, so I'll pop the cap now and swap that out. So much for an hour's worth of cleaning the old one. Duh.