99 Q odd transmission problem

[Ludeaem]

Just started today. Had no prior symptoms. So every gear shifts good except for when the car wants to go into 4th (O/D). I shifts ok intially but then starts to stumble and jerk randomly. So i have to click the O/D button to stay in 3rd. No other gear does this but 4th. ANyone have any ideas?

UPDATE:***** So im still having the problem but i've narrowed it down. Thinking it may be the TCM. If you put the car in first gear it should stay locked in that gear. It doesn't! It shifts to 2nd and starts to buck. Faulty TCM or whatever sensor that may be??
Modified by Ludeaem at 9:52 AM 12/13/2008

[maxnix]

Most likely lack of intake path and fuel system maintenance.

No codes?

Be sure to complete your profile so we know which car you have without having to mention it every time you post.

[Ludeaem]

well i did put a cone filter on the other day and changed the diff fluid to some mobil one synthetic. But yea, codes.

[maxnix]

well i did put a cone filter on the other day

You'll lose 30 HP in the summer and have accelerated wear on your engine in the meantime and then also.

Don't discard your OEM CAI.

[Ludeaem]

30 is a stretch but i know about the disadvantages. Im going to build a heat shield here in a few months (if this car still works that is).

[bullittandy]

We need more info. Symptoms, description etc.

[maxnix]

30 is a stretch but i know about the disadvantages. Im going to build a heat shield here in a few months (if this car still works that is).

Not on a 100 degree day with underhood at 180° F!

Good luck with your car!
Modified by maxnix at 9:09 AM 1/16/2009

[Ludeaem]

We need more info. Symptoms, description etc.

random jerking in OD.. then it kicks itself out of 4th back into 3rd. NO CODES. Its weird and pissing me off. BTW Maxnix i could care less about power. Its an anemic v8. Plus in Indiana it rarely gets to 100. Like i said if the car survives or i want to deal with the problems i'll take pictures of the final product. I am planning to have it look OEMish with the heat shield and rubber seals.

[maxnix]

random jerking in OD.. then it kicks itself out of 4th back into 3rd. NO CODES. Its weird and pissing me off. BTW Maxnix i could care less about power. Its an anemic v8. Plus in Indiana it rarely gets to 100. Like i said if the car survives or i want to deal with the problems i'll take pictures of the final product. I am planning to have it look OEMish with the heat shield and rubber seals.

"Anemic" before or after the cone filter? Most here are pretty strong for a 250 cu. in. V8 in a 2 ton car.

Couldn't be part of the problem, could it?

[Ludeaem]

anemic compared to modern v8's. Its a strong motor from what i read. I thought it was the MAF at first but i put it in neutral and rev'd it and no stumble. THe problem persists and i think a full flush is in order. Maybe that holds the cure. I'll make sure to find a BG shop around here. If anyone has any other ideas let me know. Thanks for the help peoples

[JOHNQ]

this sounds like another y33 ignition coil related misfire to me. the misfire at times is very subtle and causing you to give more gas telling the engine to downshift for more power. if im right, keep driving it and floor the gas at these episodes of misfire and force the computer to generate a code telling which cylinder/coil is misfiring.

[Ludeaem]

this sounds like another y33 ignition coil related misfire to me. the misfire at times is very subtle and causing you to give more gas telling the engine to downshift for more power. if im right, keep driving it and floor the gas at these episodes of misfire and force the computer to generate a code telling which cylinder/coil is misfiring.

you may be on to something. If i let off the gas or have very little throttle it doesn't do it. Maybe it has to do with engine load and the ignition?

[Ludeaem]

update on first post

[maxnix]

If you put the car in first gear it should stay locked in that gear. It doesn't! It shifts to 2nd and starts to buck. Faulty TCM or whatever sensor that may be??

No, it doesn't! it upshifts when required. You would be the first with a faulty TCM.

[Ludeaem]

No, it doesn't! it upshifts when required. You would be the first with a faulty TCM.

hmm i swear thats the first time its done that. Damn car. I have no idea then. I put the stock airbox back on too and of course that didn't do anything.

[Ludeaem]

where is Q45 tech when you need him? Still having issue. Car does not like 4th gear! What the hell

[maxnix]

Please comment on condition of ATF via white paper towel test and smell.

Maintenance history?

[bullittandy]

Have you actually done anything?

It would make sense to flush the transmission fluid to start and then see what happens.

[Ludeaem]

atf is about 45K miles old which i know is overdue but is still a nice shade of red. I need to smell but right now its -4 out so i don't know how much i could take in haha. I haven't done anything but just drive the car in 3rd gear. Thank God third gear locks up so its drivable. I will change it soon. But you really think its a fluid issue? Its just strange how the car kicks it out of OD.

[Q45tech]

Check for knock sensor code and things that would lower engine torque output.Does bucking get worse with AC compressor engaged?

[Ludeaem]

it does have both knock sensor codes. Um not sure like i said within 2 seconds in OD the car jerks and then pops it out of the gear. then tries to go back in 4th.. then out, in, out on and on. So there really isn't anytime to check that theory but i will try. Remember this is ONLY 4th gear.

[Ludeaem]

some good news i suppose. I got it to stay in 4th gear tonight for an extended amount of time and sometimes (for 10-15 seconds) it would not even jerk. Seemed dependent on throttle pressure? Maybe? Seemed like the less gas the more apt to staying in that gear without issues. Maybe TPS? Could be MAF too i guess. Both i can get a solid ohm reading on correct?

[Q45tech]

Replace knock sensors!

[Ludeaem]

ok update. I have since flushed the transmission fluid (bg flush) and the problem persists. I am going to get voltage readings from my TPS first to see if they are in spec and if that is ok i will then believe it has to do with one or both solenoids being short circuited or damaged in some way. Maybe line pressure solenoid valve? What do you think Maxnix? q45tech? Is this a decent path to be looking down?

[maxnix]

It won't hurt, but if KS codes are erased and reappear quickly, then that is where I would start the diagnosis.

Should be easy to test resistance through harness. Start there.

[bullittandy]

You mentioned that you have knock sensor codes which means that they are not working and you are likely losing a significant amount of power as a result-maybe as much as 20-30 ft lbs of torque.

It is likely that the lack of power is causing the transmission to shift strange-essentially you are lugging the engine.

Replace the knock sensors, replace the knock sensors, replace the knock sensors, replace the knock sensors.

[NightRiderQ45]

Replace knock sensors!

I mean, Tech told you this back in Jan.

[Ludeaem]

I mean, Tech told you this back in Jan.

Right but im 99% sure this car had the knock sensor codes before i bought it. and remember that the car didn't do this until after a month after purchasing it. I know knock sensors retard timing when they go bad (i had a 96 maxima before this) but they make that much of a difference to make the transmission act up??

[bullittandy]

Right but im 99% sure this car had the knock sensor codes before i bought it. and remember that the car didn't do this until after a month after purchasing it. I know knock sensors retard timing when they go bad (i had a 96 maxima before this) but they make that much of a difference to make the transmission act up??

No, they do not.

Under no circumstances should you replace the knock sensors in an attempt to solve your problem. You should instead test your TPS and the solenoids in the transmission like you speculated about in earlier posts and report back with results.