99 LC - Transmission "Shudder" and rough idle when stopped in gear (2 Viewers)

[Igoteyedeas]

Hey guys,
So after pouring over dozens of threads on here and conducting hours of Google research, I have yet to find anyone with the same issue. So I thought I'd put it out there and see if anyone has experienced something similar and was able to fix it.

So I have a 1999 Land Cruiser and I've recently done a ton of work to the engine including:
• New timing belt/water pump
• New spark plugs (and replaced a bad coil pack on cyl.5)
• New valve cover gaskets
• New Fuel Filter
• New intake filter
• Cleaned MAF, TB and hit all electrical connections with cleaner

I'm still having an issue when the truck is warmed up, at stop lights it will feel almost like intermittent misfires and the truck will shudder. When I take it out of gear (N), it immediately gets better. Also, when I pull away from a stop light, it hesitates for a moment as I give it acceleration and kind of lurches forward for a moment before going back to normal. No CEL's and it runs great in all other scenarios.

Driving 2-3 miles to and from work every day, it usually happens at the end of my trip and it's almost unbearable during long road trips when I have to come to a stop. Has anyone had a similar issue? I've checked all vacuum hoses for leaks, cleaned everything I could think of and I'm at the point where I'm starting to get desperate and start throwing parts (read: money) at the problem. One thing I haven't done is check the coils as it might be an intermittently going out, but not sure on the procedure to do so?

Any guidance is much appreciated!

 

[Spike555]

Your touqre convertor is not unlocking. I do not know where the plug for it is, but find it, uplug it and see if there is any change.
You can leave it unplugged forever but MPG will suffer, there is a solenoid that locks/unlockes it, I am not sure where that is, usually inside the transmission.
I had this problem with a Oldsmobile I had, eventually I got used to the lower MPG and it became a commuter car instead of the family car, drove it that way for 60k.

 

[Igoteyedeas]

Thank you, Spike. I'll poke around and see if I can determine where that solenoid is so I can give it a shot. Any other thoughts are always appreciated!

 

[gatormark91]

First thing - have you checked the trans fluid level? The transmission will do this if it is very low.

Also - the fact that it is not doing all the time, only at the end of the trip, makes me think your trans fluid is old and has broken down and is not working right when it is hot. Might be time to drop the pan, clean it out, replace the filter, and do a trans cooler line drain/refill (NOT A POWER FLUSH, EVER).

 

[mmaakk]

I had something very similar happening..My truck had 278k miles and coils started to go out one at a time, so I changed them all along with plugs and it ran great. After 20k miles of changing all my coils and spark plugs the same happened again. Cel was not going off which made it harder to diagnose. Turns out cylinder 8 closest to windshield passenger side coil was torn at the tip, and the plug broken ( all the ceramic loose from the metal!). I have no idea what happened but after changing them out she ran like a champ again. I'd check them all again even if you just changed number 5 out. It's about the time they all start failing.

 

[BlueMica]

I have recently experienced similar issue as the OP is reporting. The shuddering/rough idle typically happens when I'm stopped in traffic within the first few minutes of driving. It is intermittent.... 197k miles on my rig.

 

[Igoteyedeas]

I have recently experienced similar issue as the OP is reporting. The shuddering/rough idle typically happens when I'm stopped in traffic within the first few minutes of driving. It is intermittent.... 197k miles on my rig.

Per GatorMark's comment, I haven't done a thorough fluid exchange so I'm going to give that a shot before jumping to any other conclusions. I should have a chance to get this done by the end of the weekend, so I'll report back on here with the results.

 

[flintknapper]

Per GatorMark's comment, I haven't done a thorough fluid exchange so I'm going to give that a shot before jumping to any other conclusions. I should have a chance to get this done by the end of the weekend, so I'll report back on here with the results.

Yes, let us know. I wouldn't jump to the conclusion that the 'shudder' is coming from the transmission. Lots of causes for that.

The A343F transmission is pretty reliable.

 

[Igoteyedeas]

Yes, let us know. I wouldn't jump to the conclusion that the 'shudder' is coming from the transmission. Lots of causes for that.

The A343F transmission is pretty reliable.

Totally agree re: the reliability of the A343F, but given the behavior that it only happens after being at operating temp for a while and it completely stops when put in "N", transmission seems like a good place to start.

While I've been doing my best to baseline the truck over the past year and a half, one thing I've learned is that the LC's legendary reliability is partially dictated by how well it was maintained. That said, the P.O. didn't know squat about how to take care of a car/truck/anything so I may experience some unusual issues moving forward.

I plan on getting the tranny fluids sorted Friday morning so I'll report back after!

 

[Spike555]

I agree it should not be anything wrong with the transmission, if you were to unplug the torque converter if there was no change you could plug it back in.
I hope it is something simple and cheap.
Keep us posted.

 

[2001LC]

I fought the "D" vibration for some time. I did minor tune as you but it kept coming back. Until I did one very simple thing: I disconnected the battery for 30 minutes while doing the minor tune-up.
Vibration and shake at Idle

Do you smell fuel when idling:

Some other issue we're now seeing with todays' (corn gas additive) gas, cheap gas or rigs that sit without been driven daily is fuel system problems. Water builds in fuel tank and sit at bottom where fuel pump picks up.

A bad fuel pressure regulator (FPR) may show up as; MPG that is erratic, even though driving habits are consistent. This could be sign FPR needle has damage by rust.

Fuel injector are also being damage also. FIS has tested 16 fuel injector for me in the last year, 1 on a 2001 w/215K, the other a 06 w/194K miles. Between the two rigs FIS found a total of 7 did past inspection. Either issue with spray pattern (rough idle and poor performance) or leaking (hard start) due to rust on needles of fuel injectors.
When to replace fuel injectors

I love the results I get from full 12qt transmission flush with M1 MV full synthetic ATF in 98-02 series 100. I use it in the power steering as well. Don't know of this will help you but it can't hurt.

One other issue I've only seen in mud, is flex plate crack. This, IIRC manifest itself as a vibration and is sometimes thought to be exhaust leak. You "may" be able to pull inspection plate and look up at back side and see. I say "may" because this is not something I've every had to deal with or tried.

Good luck on your hunt! Hope it just a battery disconnect to reset ECM, and stay away from cheap gas.

 

[Igoteyedeas]

So finally got it sorted today and it turns out it actually was a misfire in cylinder #5. When the transmission was in gear it just amplified the misfire, thus making it seem like more of a transmission issue.

Replaced the ignition coil and all is well again. Now on to the newly leaking CV boot that started today.

 

[flintknapper]

So finally got it sorted today and it turns out it actually was a misfire in cylinder #5. When the transmission was in gear it just amplified the misfire, thus making it seem like more of a transmission issue.

Replaced the ignition coil and all is well again. Now on to the newly leaking CV boot that started today.

Good deal. Thanks for reporting back...so that others can benefit from your experience.

As previously stated....'shudder' is seldom from the A343F transmission. More often a fuel/spark/vacuum problem and often times intermittent.

Might as well re-boot both CV's when you have time. Take a look at your ball joints and other steering/suspension related components while you are at it. As our vehicles age...any of the rubber parts have probably seen better days (bushings, boots, etc), so they need to be looked at and accessed.

 

[smithytailor]

So finally got it sorted today and it turns out it actually was a misfire in cylinder #5. When the transmission was in gear it just amplified the misfire, thus making it seem like more of a transmission issue.

Replaced the ignition coil and all is well again. Now on to the newly leaking CV boot that started today.

How did you figure out which cylinder it was?

 

[Igoteyedeas]

How did you figure out which cylinder it was?

Had to hook it up to an OBD2 scanner that could provide real-time data (not just codse). Also, got the CV boot sorted so the truck is ready for the Sequoias this weekend!

Ironman Front Bullbar Installed

• Igoteyedeas
• Aug 16, 2017

 

[dahlmaker]

So finally got it sorted today and it turns out it actually was a misfire in cylinder #5. When the transmission was in gear it just amplified the misfire, thus making it seem like more of a transmission issue.

Replaced the ignition coil and all is well again. Now on to the newly leaking CV boot that started today.

@Igoteyedeas
I've got the same issue. Do you have a good mechanic in SoCal? I'm in Inglewood. Thanks.

 

[nspindel]

Check plugs and coils

 

[dahlmaker]

Check plugs and coils

Will do. Thanks!

 

[ghong14]

So finally got it sorted today and it turns out it actually was a misfire in cylinder #5. When the transmission was in gear it just amplified the misfire, thus making it seem like more of a transmission issue.

Replaced the ignition coil and all is well again. Now on to the newly leaking CV boot that started today.

Did you use a diagnostic tool? If so which did you use?