PLEASE DON'T WASTE YOUR TIME BY SAYING "Do a Idle Relearn" Its not the case, even if it was, It would be impossible with the terrible ways this car is running.

I Have a 3.1 V6 Auto Camaro that has a couple of weird problems.

Problem 1: My car SOMETIMES runs VERY TERRIBLE, by sometimes i mean the car will be running really good then suddenly run rough. by run rough i mean the following symptoms

-Idle is somewhat rough
-Car missfires alot
-once in a while the car will just jump up to 2000-4000 RPM on ITS OWN and idle at that rate for a long time (The only way i can ever temporarly fix this is put the car in gear and lay it on the rug for a second, I can then place back to Park and the car will idle fine again.)
-Car will bog out and stall after time if idling at a normal RPM
-Car will very easily stall while in gear/reverse, Or if gas is depressed very quickly (Unless the Idle was very high as stated above)
-Car shakes violently (Feels like the timing is not right)

Sometimes If i turn the car off, and then turn it back on, It will run perfectly fine. after a random amount of time the car will show these symptoms again.

Me and my father replaced the spark plugs and cleaned the fuel rail and injectors out to see if that would help; it did not.

Problem 2: While travelling at speeds over about 75km/h my transmission pulsates (CONSTANTLY shifts up and down and up and down).
If i manually drop down the gear down (Regular Drive) the car will then pulsate with the gear below that one. This Really bothers me due to the fact that i know a transmission will only shift a certain amount of times before needing a replacement. and my car shifting itself 50 times per minute doesnt help one bit. (It is also a very uncomfortable and stressful ride)

 

quick observations:

short
tps
timing issue (module may be bad, dizzy off, timing chain stretch)
egr
tcc (when it rpms go up& down in 4th, is the speed affected)
torque convertor dying

is the SES light coming on at all?

 

also everytime u unhook the battery u need to do an idle relearn or the car will stall out when comming to a stop or idling in gear

 

the transmission isn't ECM controlled.... the torque converter clutch is though.

i would look at the PROM/ECM being junk, or at least the +12V and ground circuits for it being flaky.

 

Thanks for the reply. Couple questions

1. Is there a way to test my PROM/ECM (I'm assuming a scanner)
2. If my ECM/PROM was completely disabled would my car run? Or would it stall/not start

 

use the paper clip method to flash the check engine light so u can puull any trouble codes stored in the ecm

 

Your best bet is to use a scan tool of some sort. If you have a laptop can get an ALDL interface cable and use Tuner Pro RT as the scan tool. The use of a scan tool will also let you see what the ECM is seeing for sensor data.

With a completely disabled ECM the engine won't run. With a partially bad ECM the engine can run bad, with an ECM that can't run from the PROM the engine will still run. But in a funny sort of way.

Check the resistance of the injectors, any that are under 12 ohms is bad. Replace them all.

RBob.

 

Yeah, what they said. B4 you go checking/replacing the ECM, checck the charging voltage at the battery(with the enine running). When I checked the one that was in the car, it was charging at 19 volts (max is 14-15v). Rebuilt unit was good and the idle and performance improved somewhat. It seems that the extra voltage can mess up the way the ECM performs.

 

^What he said^, once the vehicle voltage goes over 17.1 volts the ECM shuts down the quad driver outputs. The injectors will still fire, but all the other stuff (fan, EGR, CCP, TCC, etc.) the outputs are shut down.

I'm not sure if the ECM compensates for this by bypassing the logic to operate those devices either. Basically, it is a last ditch effort to prevent stuff from going up in smoke.

RBob.

 

Alright, I will do a bunch of checking when I have the time.

*On another note, the other day I moved my car into the bodyshop i work at (Leaving the car there while its not running right) and washed the roadsalt off so my car doesnt rott while sitting unusable, i barely got the car into the shop. When i went to start the car again it wouldnt even start, it would turnover fine but wouldnt run. We had to push the car out of the shop. It smelled like raw fuel after that. (Like the car flooded) Just thought this might help to diagnose my problem.

 

Sounds like ICM to me.