Completely Baffled; Help with my 97 Cavalier?

Question

2.2 L
Manual Transmission
Base Model
Chevy Cavalier;

ITS NOT RUNNING HOT!
Temp stays pretty steady going from 180-190.

3 Aftermarket gauges; Volts, Oil Pressure & Water Temp
I put these in after it started acting up to monitor what it was doing.
Exhaust with NO CAT (Running test pipe)

What its doing;

In hot weather/ when running for long period of time (Aprox. 30 Minutes)
It will gain a lot more back pressure than it normally has (you can hear it)
Bogs down, (you can feel it bog down & start losing power)
Idles rough (starts to idle low almost shutting off)
Then Shuts off

It will start back up, but will not stay started;
If it sits for an hour or two it will run fine for another half hour then do it again;

In COLD weather it will not do it, its done it maybe twice, but was just sitting there idling.

Its throwing codes for
Cam Shaft Position Sensor
Throttle Position Sensor
Crank Sensor
O2 Sensor
Evap Canister Leak
still even after replacing what the codes were throwing;

List of new parts;

Coil Packs
Vacuum Lines
Crank Shaft Position Sensor
Spark Plugs
Spark Plug Wires
Flushed & Replaced Coolant
Oil & Oil Filter
Fuel Pump
Fuel Tank & Oil Pan (Both got punctured, but not relevant)
Oil Pan Gasket
Fuel Lines
Radiator Cap
Fixed Evap Canister Leak (Line popped off)

Any Help Will Be Much Appreciated

Answer 1

there is a coolant sensor at the radiator...it,s the sensor that provide,s temperature information to your computer. not the same one that regulate,s your dash gage...it is responsible for electric fan operation through the computer...have that checked as well as an actual temperature reading at the radiator...your local radiator repair shop or reputable mechanic or dealer ship can provide this service for you...good luck!....P.S....have electric fan operation checked as well...eventhough it,s not overheating that sensor [ if defective] will make your computer think it is & will try to adjust timing & air/fuel ratio,etc.

Answer 2

My first impression is also that you have a bad PCM. Bizarre and vast assortments of codes along with failure at higher temperature leads me to this conclusion. My experience with electronics and integrated circuits tells me that such components are FAR more likely to fail when hot rather than cold. In fact, it's a very common troubleshooting trick to use a spray can of solvent that instantly freezes circuit boards to locate and diagnose failing circuits. Temperature being a solid variable almost certainly confirms the diagnosis. If you can, try heating it up with a light bulb or some other such method on a cold day to try to recreate this problem. I believe the computer on this model year is also under the body of the vehicle near the driver's side. (I have a '99)



The only other thing I can think of that you could try is the "crank relearn procedure", which can only be performed with a GM Tech-II or other expensive scan tools. Why this would cause a problem only in hot weather... Who knows, possibly the ignition timing is off enough to cause hot spots to develop in the cylinders resulting a misfire condition that you do not get in cold weather. It's possible this could happen without seeing an increase in coolant temperature.



Lastly, "back-pressure" along with a rough idle and stalling could be a failing EGR valve... If yours has one. The reason why I'm including this last is that my 1999 Cavalier does not even have this part. But, if yours does it would be worth checking out.



Most importantly... Be careful if you decide to swap the PCM for another, as there have been cases where the problem that blew the first one damages another in a matter of minutes!

Answer 3

the majority has spoken....Mitsubishi Galant is the greater useful decision. The Galant has greater useful comments than the Cavalier. The Cavalier is a smaller motor vehicle and an somewhat elementary transportation. The Galant a minimum of has lots greater useful centers with greater useful indoors high quality than the Cavalier. The Cavalier is in simple terms clunky.

Answer 4

Wow, interesting issue.



One thing that I noticed that hasn't been looked at or replaces is the PCM(computer). Do you have access to a spare one to try out? They can do some waaaaacky stuff when they're on their way out. It doesn't mean they always do it too...