6th Gen ('00-'05): 2002 Monte Carlo SS Dale Earnheart 3.8
#1
11-22-2021, 09:06 PM
2002 Monte Carlo SS Dale Earnheart 3.8
I have an engine code PO300
I started car and used a Lazer temp gun to check exhaust at head and some are about 150-180° but middle one at front of car is saying 320°
I'm not sure why that cylinder is so hot
But also if in park and rec engine up to 3800 rpm's it pops pretty bad through exhaust..
Could it be a bad cat??
Any help will be appreciated
I started car and used a Lazer temp gun to check exhaust at head and some are about 150-180° but middle one at front of car is saying 320°
I'm not sure why that cylinder is so hot
But also if in park and rec engine up to 3800 rpm's it pops pretty bad through exhaust..
Could it be a bad cat??
Any help will be appreciated
#2
11-23-2021, 09:21 AM
Sounds like the 150-180* ones are the problem. I think 320* is even a little low. Hows your plugs and wires look? Could be an injector problem, but it would be strange for several injectors to fail all at once. You might need to get a scanner and get some info, which cylinders are mis-firing.
If it was a plugged cat, I would think you would not have such a temp difference. Actually I would think if the cat was plugged, you have much higher temps on all runners.
If it was a plugged cat, I would think you would not have such a temp difference. Actually I would think if the cat was plugged, you have much higher temps on all runners.
#3
11-23-2021, 02:48 PM
Thanks for reply! I just ordered a tune up kit
new plugs coils and wires and fuel filter.
The car sat for about 3 years. It had about 2 gallons of gas in it (old) I took out what I could. so I added 10 gals of premium. It started up after some cranking
It does shake a little as it idles. It first threw a PO118 CTS code and I installed new sensor.
That code I erased and it never came back
Then this one came up!
That why I ordered a tune up kit.
i may just order all new inject too.
I'm hoping this will fix it!
new plugs coils and wires and fuel filter.
The car sat for about 3 years. It had about 2 gallons of gas in it (old) I took out what I could. so I added 10 gals of premium. It started up after some cranking
It does shake a little as it idles. It first threw a PO118 CTS code and I installed new sensor.
That code I erased and it never came back
Then this one came up!
That why I ordered a tune up kit.
i may just order all new inject too.
I'm hoping this will fix it!
#4
11-23-2021, 02:50 PM
Thanks for reply! I just ordered a tune up kit
new plugs coils and wires and fuel filter.
The car sat for about 3 years. It had about 2 gallons of gas in it (old) I took out what I could. so I added 10 gals of premium. It started up after some cranking
It does shake a little as it idles. It first threw a PO118 CTS code and I installed new sensor.
That code I erased and it never came back
Then this one came up!
That why I ordered a tune up kit.
i may just order all new inject too.
I'm hoping this will fix it!
new plugs coils and wires and fuel filter.
The car sat for about 3 years. It had about 2 gallons of gas in it (old) I took out what I could. so I added 10 gals of premium. It started up after some cranking
It does shake a little as it idles. It first threw a PO118 CTS code and I installed new sensor.
That code I erased and it never came back
Then this one came up!
That why I ordered a tune up kit.
i may just order all new inject too.
I'm hoping this will fix it!
#5
11-23-2021, 10:05 PM
Sounds like the 150-180* ones are the problem. I think 320* is even a little low. Hows your plugs and wires look? Could be an injector problem, but it would be strange for several injectors to fail all at once. You might need to get a scanner and get some info, which cylinders are mis-firing.
If it was a plugged cat, I would think you would not have such a temp difference. Actually I would think if the cat was plugged, you have much higher temps on all runners.
If it was a plugged cat, I would think you would not have such a temp difference. Actually I would think if the cat was plugged, you have much higher temps on all runners.
I bought new coils plug wires and plugs and a fuel filter
I'll try that first and see what happens!
I'll post results after
Thanks for reply
#6
11-24-2021, 08:14 AM
Ive also had MAFs, MAPs, coilpacks, FPR, o2 sensor, and an IAC cause multi cylinder misfire.
The MAF is easy to test, just unplug it and see if the issue gets better. -This is not 100% tho. It could get better when unplugged but a couple miles down the road the issue may come back. Works most of the time tho.
FPR, disconnect the vacuum hose while the car is running and see if it smells like gas OR watch the FPR itself to see if it spits out any gas/with that hose still disconnected. That could take a few minutes to happen. If so its bad.
Coilpacks, MAP, o2 sensor, and IAC need to be tested with a multimeter I believe but not sure what the readings should be. Ive always had a bunch of spares to swap around.
Check for vacuum leaks. I use an unlit propane torch around all the lines and watch for idle fluctuation.
Dont rule out the plugged CAT tho, I just think its unlikely.
You want to get the FPR checked quick tho, if its that it can blow up the intake manifold while youre trying to start the car.
The MAF is easy to test, just unplug it and see if the issue gets better. -This is not 100% tho. It could get better when unplugged but a couple miles down the road the issue may come back. Works most of the time tho.
FPR, disconnect the vacuum hose while the car is running and see if it smells like gas OR watch the FPR itself to see if it spits out any gas/with that hose still disconnected. That could take a few minutes to happen. If so its bad.
Coilpacks, MAP, o2 sensor, and IAC need to be tested with a multimeter I believe but not sure what the readings should be. Ive always had a bunch of spares to swap around.
Check for vacuum leaks. I use an unlit propane torch around all the lines and watch for idle fluctuation.
Dont rule out the plugged CAT tho, I just think its unlikely.
You want to get the FPR checked quick tho, if its that it can blow up the intake manifold while youre trying to start the car.
Last edited by wht02monte; 11-24-2021 at 08:19 AM.
#7
11-24-2021, 01:30 PM
Ive also had MAFs, MAPs, coilpacks, FPR, o2 sensor, and an IAC cause multi cylinder misfire.
The MAF is easy to test, just unplug it and see if the issue gets better. -This is not 100% tho. It could get better when unplugged but a couple miles down the road the issue may come back. Works most of the time tho.
FPR, disconnect the vacuum hose while the car is running and see if it smells like gas OR watch the FPR itself to see if it spits out any gas/with that hose still disconnected. That could take a few minutes to happen. If so its bad.
Coilpacks, MAP, o2 sensor, and IAC need to be tested with a multimeter I believe but not sure what the readings should be. Ive always had a bunch of spares to swap around.
Check for vacuum leaks. I use an unlit propane torch around all the lines and watch for idle fluctuation.
Dont rule out the plugged CAT tho, I just think its unlikely.
You want to get the FPR checked quick tho, if its that it can blow up the intake manifold while youre trying to start the car.
The MAF is easy to test, just unplug it and see if the issue gets better. -This is not 100% tho. It could get better when unplugged but a couple miles down the road the issue may come back. Works most of the time tho.
FPR, disconnect the vacuum hose while the car is running and see if it smells like gas OR watch the FPR itself to see if it spits out any gas/with that hose still disconnected. That could take a few minutes to happen. If so its bad.
Coilpacks, MAP, o2 sensor, and IAC need to be tested with a multimeter I believe but not sure what the readings should be. Ive always had a bunch of spares to swap around.
Check for vacuum leaks. I use an unlit propane torch around all the lines and watch for idle fluctuation.
Dont rule out the plugged CAT tho, I just think its unlikely.
You want to get the FPR checked quick tho, if its that it can blow up the intake manifold while youre trying to start the car.
ill check the Maf ,FPR today and others you mentioned and see what happens..I'll post results
#8
11-24-2021, 04:45 PM
Thanks for reply. I have checked coils and they are at approx 5.45 so I I bought a kit with new coils plugs and wires new fuel filter I haven't checked anything else after replacing CTS my radiator fan is still running constantly.
ill check the Maf ,FPR today and others you mentioned and see what happens..I'll post results
ill check the Maf ,FPR today and others you mentioned and see what happens..I'll post results
When I get back from thanksgiving I'll do plugs and wires and gas filter and try it again
I did the FPR test and no gas coming out. Of it while running.
I notice when starting car I had Maf unplugged and it ran same wether it was plugged in or not.I did check V's with key on and probed harness. There is 13 V's on the one wire..
#9
11-26-2021, 11:14 PM
Join Date: Apr 2010
Location: Mentor, Ohio
Posts: 12,200
I trust salvage factory coils more than after market replacements. You may want to have the ICM tested. I admit, I find it rare that factory coils fail. Also, disconnecting the vac line to the FPR and ensure no signs of fuel in there (I forget, but there is a year or two GM had a bad batch of FPRs from their supplier).
Basic tune up like to mentioned (plugs, wires, fuel filter) are all good measures.
Basic tune up like to mentioned (plugs, wires, fuel filter) are all good measures.
#10
11-26-2021, 11:47 PM
I agree! That's where I'm starting is a full tune up!
we shall see what happens after
Thanks for reply
we shall see what happens after
Thanks for reply