Does your scan tool have the capability to look at the sensor trace from B2S1. If so, how does it look? Smooth transitions or random sharp peaks? If it is random sharp peaks, the sensor is gone. If they haven't been changed, I would recommend you change the upstream sensors, both B1S1 & B2S1 which are located in the y-pipe. B1S1 is on the driver's side while B2S1 is on the passenger side directly ahead of the 'y' in the y-pipe.

As I suggested earlier, it is possible that the PCM (VCM,ECM whatever you want to call it) is at fault for this. The cheapest route to go would be to grab one either online or from a local recycler in your area and install it. Worst case is it doesn't work. Best case is it works and you then need to have a CASE learn done for the new PCM to learn the specific correction factor between true engine position and what the crankshaft position and camshaft position sensors are telling it.

I still think this is a grounding problem somewhere that is affecting the sensors and possibly the ignition system.

 

I can record live data for 20 frames. Should I do this when the car is idle and at operating temp? It idles fine. When I accelerate ( step on the gas quickly) even in park after it's warmed up it will hesitate and bog down, backfire, and acting like it's not getting any enough gas. I can get it to sometimes reach higher RPMs if I slowly increase the throttle instead of stepping on it hard and fast.

Really though it was the misfiring thats was causing that problem. Now the misfiring iscorrected I still have it.

What about a plugged up cat? Can it get worst when the car reaches operating temp and work OK when the car is cold (less plugged up)?

Thanks,
Brian

 

Its the Cat... I worked on a 2000 with simialar conditions.. I believe the code it stated was a lean condition.. Took it to Firestone and they wanted said a vacuum leak. I took it to the dealer and it was the converter.. And the best part of it was it was still under warranty and they paid for it..Runs perfect now.

 

A plugged cat wouldn't perform good at one point, then all of the sudden clog up, only to unclog a few minutes later... One way to know for sure is to remove the O2 sensor directly ahead of the catalytic converter (B1S2) and drive it like that. If the problem is aleviated, it's your cat. Catalytic converters are warrantied much longer than the factory warranty, but I don't think yours would still be covered.

I'm leaning towards a ICM problem. You can remove the ignition control module and take it into Advanced or Autozone and have it tested. Have them test it 10-15 times in a row and see if it still passes. The ICM is mounted onto a small heat exchanger for cooling. Your problem seems to be related to heat. Also, there should be some thermal paste between the ICM and the plate it mounts on. If this is missing, try putting some dielectric grease (temporarily) onto the back and see if that helps.

 

I haven't check the ICM yet but did pull it off clean off the old heat sink compound and reapply new stuff. Well I Replace both Upstream O2 sensors and the vehicle seems to be running much better. No codes!Also after a 30 mile drive to work no signs of the engine losing power anymore. Not yet anyways. It was doing it everyday driving to work and back and today it was fine. Could the O2 sensors be the cause of such a problem. Maybe when they finally heat up? It like it was the engine was starving for gas. Hopefully now I can get it in to get it inspected but still have to get the computer to run it system checks. I tried to do the GM drive thing to get the IM ready tests performed but never works for me. Still have Cat, EGR, and Evap to pass yet.

Thanks,
for the help. Hope this is the conclusion of this problem.

Brian

 

Glad it's working for you now... With all of those codes... Well, time will tell.

It is possible that the ICM wasn't being properly cooled prior to you cleaning it and reapplying thermal paste. It is also possible that the misfires eventually fouled out the O2 sensors.

 

Well, back to the drawing board again. Yesterday it started doing it again on the way to work (about a 15 mile drive). The engine performs much better after replacing both upstream O2 sensors. But again it is choking after the engine gets hot. Today I'll pick up a ICM. The only question I would have about this is if the ICM was overheating and going bad wouldn't it be causing misfires? I'm no longer getting any fault codes.

Thanks,
Brian

 

I don't think the computer really tracks the ICM, it either gets a signal, or, it doesnot... If not, then the computer assumes the engine is not turning, and won't give spark, or, injector pulse. So, if you are getting Injector pulse, but NOT spark, chances are pretty good, that it is NOT the ICM.

 

The ICM (ignition control module) has nothing to do with the fuel injectors and is solely responsible for the spark timing. If the ICM is failing to initiate the spark at the proper time, it will result in very poor drivability. If the spark is occuring either way advanced, or way retarded, you won't get hardly anything for power out of it. If it is at full advance, then there would be detonation. If it is at full retard, then you just won't get anything for power. You would need a high featured scan tool to see if the timing is actually changing during operation and a timing light to verify the spark timing.

ICMs are easy enough to get tested at your local autoparts store as I suggested a few days ago.

 

The scan tool I have EQUUS INNOVA 3130 shows my ignition timing (ignition advance in Degrees). Don't know if that would offer insight as to what is going on if I monitored it. As I'm driving the amount degrees changes. I understand the concept of what you are saying but thought ignition timing was fixed. It does fluctuate some. I have captured frames with this code scanner when the problem occures but it is so erratic it is hard for me to figure out what exactly is happening. I believe I did capture frames of data (sensors) including the ign timing both when the car was functioning normally and when it was not. After capruring the data I was then plotting it with Microsoft Excel. Was doing that incase I took the car to the dealer for them to look at. But, from my past experience with them they wanted to replace things and not say it would fix the problem for sure. When I had it there they wanted to replace a single fuel injector not knowing if the one they wanted to replace was defective or not. Then they wanted to replace the PCN/ECM (the car's computer). There service manager said he wouldn't bet his pay check that it would fix the problem either. So, anyways thanks for the explaination about the timing and will try out a new ICM. I'll see if the autoparts store will test it out. I may just buy one anyways because it does't fail I guess until it gets really hot.
My past expeerience with these ignition modules was that they just tended to completely die, and never seen one that was just breaking down after sometime driving.

Thanks,
Brian

OK looking at the captured frame data (20 frames)when the engine was cold and at idle and when it was hot after a 15 mile drive shows that ignition timing advance on cylinder #1 was pretty much identical. Varied by between acouple degrees 19 - 22.