msslp04

We have owned the car for a month now and drove it from Minnesota to Oregon with no problems. It only has 17500 miles on it. Yesterday on a drive the engine was lurching some at a light and then later it killed and service engine light came on. It would start but idle high and SES on. After a while SES went away and came back a couple times but not for long but was running a little rough. Today I drove around town and had the problem more often with SES on and would stall quite a bit. I tried to pull the code but only would flash a 12, (flash - flash flash).

Any ideas on what might be the problem? Any advice would be appreciated.

Thanks, Kevin

Morley

From the description it sounds like the MAF power relay is going/gone, but this usually sets a code 33 (and gives the symptoms you have). try replacing both the MAF power and MAF burn off relays, they cost $17 each at any auto parts store (NAPA will probably be higher).

msslp04

Thanks for the suggestions. Now I need to buy the Helms manual for replacing parts. I do not know where those relays are located so any help would be great. I will get to replacing those soon.

Thanks again,

Kevin

Morley

Behind the battery on the firewall, should be 3 relays, MAF power, MAF burnoff, & fuel pump..all 3 should also be the same P/N.

msslp04

Thanks!! I looked real quick and saw them easily. I will look into getting new ones tomorrow and get them installed.

Thanks, Kevin

msslp04

I replaced the two MAF relays behind the battery and tried it again but still stalls. There is a strong smell of gas coming from the exhaust. When I closed the hood it slammed a little bit and I heard the RPMs change slightly. Don't know if that was just coincidence but it ran okay for a while and then started to act up again. One more thing, the MPG AVG display has a 99 on it when the SES light is on. Don't know if that has anything to do with anything. I tried to pull the code but all I got was 12 flashing 6 times. Any more suggestions? I would like to avoid taking it to the Chevy dealer but I might not have a choice. I am not the greatest mechanic but I try. I ordered the Helm manual yesterday so I have a wait for it.

Thanks for any help!

Kevin

Morley

Next step. Start the car and let it warm up. when it starts acting up, gently but firmly, rap on the MAF housing with a screwdriver handle. Take notice of the idle quality while doing this. If the idle gets better or worse shut off the car and disconnect the MAF. Restart the car (SES light should come on giving a code 33), now, is the idle better, worse or the same?

msslp04

Thanks for sticking with me on this Morley. I went out and started it and it did not act up!! I let it warm up and then tapped the MAF housing to see what would happen and no change. I unhooked the MAF and started, got the SES light and the RPMs were about the same. I checked the code and got a 33 like you said it would. I drove it around town for a bit and no problems. I guess I shouldn't complain but this is a little frustrating. I hate intermittent problems. I will drive it tomorrow and go get the oil changed since it has been 3000 miles. I will see how it goes. Thanks and hopefully I won't be posting on this thread again but I doubt it. Let me know if there is something else I can do.

Thanks again, Kevin

gbody5

I had the same intermittent symptoms, changed relays, MAF sensor, injectors (leaking anyway) ended up being faulty ECM.

Good Luck!

msslp04

Thanks for responding. I took the car to the Chevy dealer and so far they found the computer not communicating. It will get a new one tomorrow and I will report back with results. Sounds like this will fix it.

Kevin

GlennS87

This type of thing happened to me. Never set a code in memory so I could never find out what was going on. When I finally couldn't connect to the ECM, I replaced the ECM and the problem has so far gone away. This happened about a month ago.

msslp04

IT IS FIXED! The ECM went out. It wasn't supposed to be done until tomorrow but the part came in and was fixed. I have neglected it and needs a bath but it is too hot to work on now.

Thanks for the help!

Kevin