1996 - Shudder on Acceleration?

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Update: it now does it generally upon acceleration. Can be 20 mph but usually starts around 30 mph and above. Doesn't matter what gear, or whether it's a hill, etc. Acceleration is the common point.


Other possibly pertinent info:

- 185k miles
- Daily driver
- Needs a [I think crank] seal, but is full on oil (only leaks on long trips)
- Just had radiator and hoses, cap/rotor/plugs/wires, new upstream O2 and MagnaFlow y pipe, water pump, timing belt, done last fall.
- MagnaFlow y pipe needs to be warrantied as one flange (on the top end betw. the manifold and y pipe) is jacked up and keeps blowing gaskets
- Randomly in the last few weeks it's had one or two moderately-less-than-perfect startups, but I didn't think anything of it until now.


Ideas I've got:

- Bad gas/something odd in the engine system making it run/start weird
- Transmission issues
- Driveline/u joints
- Something related to one of the maintenance items over the last year

Any help is appreciated as I need to use my dependable boy to try and make some money right now as times are kind of tough...
 
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Joined
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I agree with @flintknapper regarding vacuum leaks or timing.

That said, is it lifted? I swear lifting these things opens a huge can of worms. Of course that could be said of any 4x4.
Negative. Here's a list of mods (not too many):

- Keyless entry / remote start
- Single sub w/ attached amp
- ARB front bumper w/ older Warn winch

It is factory locked (3x) though, if that matters...

OH, and on the subject of timing, now that I think about it, it's been having some funny idling here and there, too. Hmm...just got to figure out how to check the timing on this one (haven't done it). Searching now.
 
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Opinions on this timing adjustment write up?

 
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I had similar symptoms... bad front shaft U joint.
I'll keep that in mind. I stopped in and talked with a shop and they said it doesn't sound like timing and it's progressed a bit just from yesterday. Now it's just doing it all the time on acceleration. The engine doesn't actually seem to be losing power either. So now I'm thinking U joints/axle/tranny/drivelines etc. which sucks. I really don't have the cash for a major fix...
 

flintknapper

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You might try taking it out the road, shifting in and out of O/D and see if you notice any difference.

Wondering if you have torque converter chatter.
 
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You might try taking it out the road, shifting in and out of O/D and see if you notice any difference.

Wondering if you have torque converter chatter.
That was actually one of the first things I did yesterday when it started happening all the time. Went from O/D to off with no change, then to 2nd with the same.

My index of suspicion for transmission issues is steadily heightening.
 
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Pull the plugs and check their condition. It sounds like a misfire from a foiled plug.
They're new last November, but from reading flintknapper's thread here (Vibration/Shudder at certain engine speed, Torque Converter?), I'm thinking there's something odd in the fuel/with the fuel system.

Will be checking plugs, using injector cleaner, and getting an oil change soon (today, hopefully).

Flintknapper, what was the ultimate resolution to your thread on "torque shudder"?
 
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He had a bad head gasket. Same thing happened to me. The coolant leak fouled the plug. I got shudder on acceleration like what you describe. I use the Toyota red coolant and my #1 plug was fouled a burnt red color. Confirmed the leak with a chemical tester.
 

flintknapper

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They're new last November, but from reading flintknapper's thread here (Vibration/Shudder at certain engine speed, Torque Converter?), I'm thinking there's something odd in the fuel/with the fuel system.

Will be checking plugs, using injector cleaner, and getting an oil change soon (today, hopefully).

Flintknapper, what was the ultimate resolution to your thread on "torque shudder"?

Had an injector that failed 'open'..... was pumping fuel into the cylinder constantly. But I also had a little torque converter chatter at times. Did a complete ATF exchange, added a tube of Lubegard and later bumped up the line pressure on my A343F when I had the pan off installing a temp sensor. Doesn't require any tools. Have not had an issue since. Have 316K miles on mine now. Shifts great...no issues.

But yours could be any number of things. Best to do what you are doing now (methodically inspecting/replacing things).

LubeGard.jpg


LC trans adj1.jpg
LC trans adj2.jpg
 
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OK, so the situation like this...

Got an oil change, nothing strange (oil looked fine), nothing changed.
Injector cleaner (but haven't driven enough because it's questionable to drive).


When I rev it in park, there is no chatter and the engine seems to be running really well, actually. And it's mostly doing it under acceleration under a load. In other words, it's more pronounced when it's working harder to accelerate such as a hill, but still does it even under light load.

Going into Toyota today for a flat-fee diagnosis. Hoping it's not the trans, but a bit worried as I'm fairly sure it's trans or driveline/axles/u joints, etc.
 
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This is on your 96? No check engine light?

I had shuddering on acceleration recently that was due to the wiring harness over the EGR pipe (lots of info on here). It was causing a misfire on acceleration/load. Inspected wires, no issues. Just needed to pull the harness away from the EGR pipe and re-insulate the harness. Mine threw a code, but maybe yours isn't as bad.
 
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This is on your 96? No check engine light?

I had shuddering on acceleration recently that was due to the wiring harness over the EGR pipe (lots of info on here). It was causing a misfire on acceleration/load. Inspected wires, no issues. Just needed to pull the harness away from the EGR pipe and re-insulate the harness. Mine threw a code, but maybe yours isn't as bad.

That's the crazy thing...no codes! I'm stumped. I'll check the EGR stuff when it gets back from Toyota today if they are stumped (they'd better not be for their flat-fee diagnosis lol). Thanks for the info! Hoping it's a cheap problem because I ain't ballin right now...
 
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OK, so Toyota got it paired down pretty quickly to a U joint, but I'm getting both front ones done because...smart.

We'll see if there's anything after those get replaced.
 

nuclearlemon

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glad that's what you found. i'll be crawling under mine hopefully soon to check the same thing. i developed a bad shudder on acceleration after running morrison trail last week. like you, mine only does it on acceleration. let up on the pedal and it's smooth as silk. rev in neutral, smooth. as soon as i put it under load, it's an issue. already checked rear shaft on the trail, so my hope is i'll find a bad front ujoint for an easy fix. unfortunately, i'm an essential worker so 9 hours a day is lost to that, i'm in the middle of selling my house, so constantly cleaning up and continuing to deal with weeds from hell, still need to clean up and unpack from morrison and prep for kelly flats this weekend and mr and mrs cdan are coming tomorrow for the night....maybe he'll work some shamanism on fat bastard. ;)
 

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