My Trac is Sick, Help!

[Chris Kulbaba]

Ugh... I just dont know what else to do with my Trac, lol...



For whatever reason when I drive the truck, every once in a while ALWAYS when coming to a stop at a light, the RPMs just totally drop off, it doesnt always stall, sometimes it seems as tho the engine is barely running, if I put it into neutral the RPMS pick up, and everything is ok. I give it a bit of gas, wait for it to settle down, then pop it into drive, and im on my way...



There is no pattern to whats happening, it just happes every once in a while, we are talking like 2-3 every trip I take bascially.



I cleaned the IAC, I cleaned the air filers, I cleaned the throttlebody, etc...



Problem still there.



I have no idea what the problem is, I was told maybe it was the vacuum elbow, but I dont get an error code or anything when this happens.



Any other suggestions are appreciated, I just dont know what else I can do.

 

[Tom Schindler]

How many miles? What year, Job 1 or Job 2?



When was your last tune-up? It sounds like you have a vacuum leak. You need to start from there.





Tom

 

[Chris Kulbaba]

01, Job2, 130,000km...



I take good care of it, I do regular maintenance.



Is the hose held on with clamps, or is it just pressure fit?



Looks tricky to get at in some of the pics ive seen.

 

[Chris Kulbaba]

I actually just went out there and took it off.



I dont see any cracks at all, looks 100% to me.



Argh.. I cleaned the MAF sensor today as well...



This is driving me nuts!



What else can I try? Fuel filter? Would that cause this to happen?

 

[Tom Schindler]

Just because there is no code doesn't mean there isn't a problem.



Since it happens at idle, your IAC valve could just need to be replaced. Doesn;t mean that is your problem, but it could be a cause.



One thing you could do, though it could be just a band-aid that works is adjust your idle screw on your TB. You problem could be a slightly lower idle and the stalling issue is caused by a lower idle and a IAC that is not working at it's peak.



I will tell you a little story my brother went through, though it has nothing to do with your problem. Vehicle...1999 Explorer. 4.0L OHV engine. 160,000 miles. (256,000 KM) During normal driving, you would hit a "flat spot" in acceleration. It would feel like the engine was stalling. If you stepped on it a little or let off of it, it would be fine. The more we drove it on our own, it felt more like the tranny was trying to shift, but was not at the right RPM to do so. So, for the heck of it, he decided to replace the Throttle Position Sensor. There is no flat spot and the tranny shifts right where is should. The only thing we could figure out is that the TPS was having a problem in sending the right signal at one point of the throttle position. The ECU was recieving mixed signals and it was trying to shift the tranny, but it had no idea what to do. Letting off the throttle put pushing down on it would put the TPS in a better position. He never got one CEL regarding the TPS or anything.



There is a lesson to be learned. Just because you don't get a CEL doesn't mean there is nothing wrong. Just because it works does not mean it is working right. Depending on the cost, it might be worth swapping out the IAC valve. That doesn't mean that will fix your problem. By tightening your idle screw, you will bring the idle up a little giving it less of a chance to stall.



On our 2000 Explorer with the SOHC engine has an IAC valve that is over $50.00. I was considering replacing the IAC when I replaced the intake manifold gaskets, but I could not justify the price myself.



Honestly, I would tighten the screw a little and see if it still does it. That might be all you need to fix the problem.





Tom

 

[Chris Kulbaba]

I can try the screw, but also I have an Xcal2, Ive adjusted the idle with that, and it didnt do anythign when I would have it idling quite high...



Is there any way to test if your IAC is working properly? Everything looked right when I clened it out today...

 

[Tom Schindler]

With the X-Cal you are adjusting the idle through the computer. With the screw, you are adjusting it mechanically. If it is done electrically, it is using the IAC valve to adjust the idle. If the IAC Valve is not in good shape, you are relying on something that is not working right.



I don't think there is a way to check it, though I am not positive.





Tom

 

[Chris Kulbaba]

I will give that a shot for sure...



But one thing that I didnt really mention is that when the idle is all messed up my tranny acts really strange, like its in too high of a gear or something... when I put it to neutral it goes back to normal...



So anyways, I started searching the net for problems iwth stalling while coming to a stop, and this came up qutie a few times, and really sounds like what is happening to me.



QUOTE: "Btw, the component responsible for the engine stall when coming to a stop is the torque converter clutch solenoid, not a control module. When the converter clutch is engaged, it provides a mechanical link between the engine's crankshaft and transaxle input shaft, eliminating converter slip and increasing fuel economy 3-4 mpg. Very common on GM fwd 3 speed transaxles (occasionally affects overdrive models) for the solenoid to become contaminated with ferrous wear particles and bind in the applied position. The clutch can't release, and the net result is the same as stopping a manual transmission vehicle without depressing the clutch pedal. "



QUOTE: "Another possibility is to look at whether or not your car's transmission is equipped with a lockup torque convertor. Sometimes, the solenoid which locks up the convertor, malfunctions or sticks, causing the convertor to "lock-up" at all times. It isn't supposed to do this, and when you slow to a stop, the car begins to jerk and finally stalls. A quick fix is to unplug the electrical connector controlling the convertor from the side of the transmission (4-pin blue on GM models). Fixing it the right way would be to have a transmission shop replace the solenoid and/or unstick the valve it operates. "



The people talking about this problem explain it exactly how it is...



In particular, I am coming to a stop, then it starts idling really strange, if I give it gas its like its in like 3rd gear or something and barely does much, when I finally put it in neutral it goes back to normal, I put it back into gear and it will stall immediately. If I rev the engine a couple times and put it in gear its okay.



Has anyone had this problem before? I definately feel the tranny issue that these people speak of.



They also said that there is somethign on the side of the tranny, the Transmission Control MOdule or whats, they say to un plug that and see if it goes away, if it does you can decide to leave it off, or have it repaired.



Make any sense?

 

[Kevin Palmer]

Although I did not read your entire last post.



If the problem ONLY happens when coming to a stop and goes away when you take the tranny out of gear, you very may well have a stuck TCC. Which basically is what keeps the torque engaged. When the vehicle stops it needs to release the torque, if not, you basically have a mechanical connection between the engine which is turn and a tranny that is trying to NOT turn.



Something will have to happen, more often, the vehicle stalls....

 

[Todd Z]

Check the Fuel filter and PCV valve....



You can also hook a vacuum Gauge to the truck, THE st pulls almost 20 PSI at idle, IF you lower than that you may have a leak..



Todd Z

 

[Chris Kulbaba]

I am going to change the vacuum elbow, and the fuel filter today.



But I am really leaning towards the torque converter problem... It seems the most logical answer to this problem. I had my tranny rebuilt last year, and it never really seemed to be 100% I had a constant squeel once warm and seemed to be coming from by the tranny.



What should I be looking at to have this fixed? Is this something I can do on my own?



Thanks everyone!

 

[Tom Schindler]

How much warranty is on the Tranny?



It may be covered.





Tom

 

[Keith Lewis]

If it's any consolation, I've had the same thing happen to my SVTF and Cobra (moreso the SVTF, both with stock tune and SCT tune, and the Cobra has an SCT switchchip), and they are both manual transmissions...

 

[Chris Kulbaba]

I have the SCT tuner too, this problem actually was apparent with or without tunes.



I am 99.8% sure its the torque converter now. I am taking it in tomorrow to have it rebuilt or replaced.



The fuel filter made no difference.





This place that I tracked down has a tranny dyno... I think I might have them test the whole works, to be sure everything is 100%...



So say they replace the torque converter, what kind of price am I looking at? And is it any cheaper to have it rebuilt instead?