2002 GTP Misfire

[DVANSANDT]

I have a 2002 GTP that I thought was flooding out. I had just about decided it was the MAF sensor but when I had AutoZone run the code last night they came back as this; po113= intake air temp circut high input, po300=random muliple cylinder misfire, p1361=ignition control circut low voltage, and p1362=ignition coil c secondary circut malfunction. Does anyone have an Idea what could be causing this? I checked to make sure the plug wires were on good and the electric plug was in good and they were. Any help would be appreciated.

[BNaylor]

Are you stock or modded. How many miles? Check the electrical connectors to the intake air temperature sensor (IAT), the ignition control module (ICM) and the PCM module. Check the PCM and secondary ignition circuit fuses.

Also, make sure the ground at the battery is good and the ground from ICM to the main engine/tranny grounding stud.

Welcome to AF.

[DVANSANDT]

Thanks for the help. I plan on checking it out tonight and will let you know what I find. The car is 100% stock and has 75000 miles on it. We love it when it runs right.

[BNaylor]

Originally Posted by DVANSANDT

Thanks for the help. I plan on checking it out tonight and will let you know what I find. The car is 100% stock and has 75000 miles on it. We love it when it runs right.

You are welcome. Pay special attention to the 1361 & 1362 codes because it indicates the PCM is not switching into the bypass mode related to the ignition control module (ICM). You can get the ICM tested at places like Autozone for free if the above suggestions do not help. Good luck!

[DVANSANDT]

I checked all of the connections last night and checked the fuses as well. Since I was there I went ahead and cleaned the grounds and checked all of the fuses but it is still doing it. This probably goes with out saying but it gets worse when you are going up hill or the motor is under a load. I will have the ICM checked tonight. Any other ideas? We have only had this car for a month or so, so I do not know the history of it. This has only started in the last week so I do not think the PO knew about it and was selling it for that reason.

[BNaylor]

Originally Posted by DVANSANDT

I checked all of the connections last night and checked the fuses as well. Since I was there I went ahead and cleaned the grounds and checked all of the fuses but it is still doing it. This probably goes with out saying but it gets worse when you are going up hill or the motor is under a load. I will have the ICM checked tonight. Any other ideas? We have only had this car for a month or so, so I do not know the history of it. This has only started in the last week so I do not think the PO knew about it and was selling it for that reason.

Since you've owned it a short period, you can do the basics such as a tuneup. Spark plugs, ignition wires, fuel filter, PCV valve. On plugs and wires stick with OEM AC Delco.

Hard to say about the past history. Typically the 1361 & 1362 codes are not good. I worked with a GP owner in the past that was never able to resolve his issue on those two specific codes. But it is better to systematically troubleshoot it before jumping to any conclusions.

I'd definitely get the ICM tested.

[DVANSANDT]

I had to have the OEM wires ordered so I did not work on the car last night. They should be here today so I will work on it either tonoght or tomorrow night.
I have thought of a couple other questions. When the guy at AutoZone was looking at the car he unhooked a couple different sensors by the intake. I did not see which ones because i was in the car starting it. After this is when he checked the codes. Would this have possable given some readings that were false? I have reset the computer and will have them recheck it this afternoon.
Is there any reason to check the fuel pressure? It seams like it is not getting enough air but I am not sure. I have worked on old cars all my life, But I am lost when it comes to computers.
Just out of curiosity, did the car you were speaking about (that never got his problem figured out) continue to cut out and run rough?
I appreciate your time and am very glad this board exists.

[BNaylor]

Originally Posted by DVANSANDT

I had to have the OEM wires ordered so I did not work on the car last night. They should be here today so I will work on it either tonoght or tomorrow night.
I have thought of a couple other questions. When the guy at AutoZone was looking at the car he unhooked a couple different sensors by the intake. I did not see which ones because i was in the car starting it. After this is when he checked the codes. Would this have possable given some readings that were false? I have reset the computer and will have them recheck it this afternoon.
Is there any reason to check the fuel pressure? It seams like it is not getting enough air but I am not sure. I have worked on old cars all my life, But I am lost when it comes to computers.
Just out of curiosity, did the car you were speaking about (that never got his problem figured out) continue to cut out and run rough?
I appreciate your time and am very glad this board exists.

Yeah, I'd make sure all sensors are properly connected and tight. The guy at Autozone should not have disconnected any sensors and then run an odb-ii scan. Cross your fingers on the P1361 & 1362 codes. Hopefully they were a fluke. Regular misfires like P0300 and P030X are easier to deal with. Definitely run another scan.

Low fuel pressure can give a P0300 random misfire code thats why I recommended checking it. At least you can rule it out.

On the other Grand Prix he had the P0300, P1361 & 1362 codes. He could definitely notice a misfire and had driveability issues. I worked with him for over 2 months on and off. He changed everything including CAT convertor, PCM, ICM, coil packs, fuel injectors, plugs, wires and even key wiring harnesses. I don't know if he ever found the actual problem.

[DVANSANDT]

I worked on it this weekend at a friends house an had no luck. We tried a different igniton coil and it did not help either. I am still getting the same codes and the car still does the same thing. I have not tried cleaning the MAF sensor yet. Is there a chance that a dealer has a better diagnostic computer than AutoZone? Will they have another way besides just trial and error? I just need to get it fixed.

[BNaylor]

Originally Posted by DVANSANDT

I worked on it this weekend at a friends house an had no luck. We tried a different igniton coil and it did not help either. I am still getting the same codes and the car still does the same thing. I have not tried cleaning the MAF sensor yet. Is there a chance that a dealer has a better diagnostic computer than AutoZone? Will they have another way besides just trial and error? I just need to get it fixed.

Yes. Its called a TECH II diagnostics machine. But it will only be as good as the Tech operating it. There are steps where the PCM can be commanded to go to certain modes like from bypass to normal related to ignition control.

BTW - Did you get the ignition control module (ICM) tested just to rule it out?

Also, I'll check my old email and see if I can hook you up with the guy that had similar problems.

[bearinns08]

check the gaps (.060 for stocks) for the misfire code
not to make anyone sound dumb here, but i'd still be working on mine if this wasn't mentioned to me...i got autolite sparkplugs (606's i think) and new wires in, and it was still running a random misfire code. i thought the plugs were pre-gapped, but i went back and took them all out and regapped them and everything runs fine now.

[BNaylor]

The P1361 & P1362 DTC error codes are causing the P0300 random misfire code. Until those codes are troubleshot and resolved he's going to be out there.

[BNaylor]

Additional info on P1361 & 1362 DTC error codes. See links below:

http://www.automotiveforums.com/vbul...ighlight=P1362

http://www.automotiveforums.com/vbul...ighlight=P1362

[DVANSANDT]

I changed the ECM and that did not help. I gave in and took it to the GM dealer last night. They are supposed to put it on their Tech II machine and check it out today. I have a buddy that used to work at the dealer and I asked him who the best guy was to check out my car. Hopefully this will give us the info needed to get this car back on the road.

[DVANSANDT]

The service tech at GM called and said that it was my converter and that it was under warranty. I hope he is correct, but after reading other posts here I am not feeling very confident about it. What do you think?