why is my car running so rich

[crazynorwegian]

So for the last month I've been trying to troubleshoot a very bad stumbling problem. I changed the spark plugs, cleaned the iac, cleaned the maf, and tried changing out the coil packs. no luck. so I took it in and pulled the codes, and it the mechanic told me the passenger side front o2 sensor was dead, and the car was running like it should at 3000ft. he didn't want to touch my car because he said it "had too many high performance mods to it" it was also throwing a rich, and lean code. I replace the o2 sensor, and the missing got a lot better. but it is still missing, and running very slow. what else could be causing my a/f mixture to be so off?

 

[Mike97gt]

most likely the maf sensor.. if you can get to use a scan tool.. run codes and see what you come up with now.. then i would monitor pid data watch your long term and short term fuel trims and maf and baro readings..

baro readings can be usfull.. if you see it rapidly changing and your not in the eye of a hurricane then you know there is a problem in the maf..

the LT fuel trims are the amount in percentage that the pcm is adding or subtracting from the base fuel map.. anything over 25 percent either way will set rich or lean codes..

the maf volatage pid sound read about .9X at idle

see if you can get this info and respond back..

 

[crazynorwegian]

well, I just disconnected my maf and took it for a drive around the block. and the problem didn't much better or worse. so I'm almost certain its the maf now...from reading, I've come to the conclusion that replacing it with a stock one is the best. I am swapping a cobra engine in next month, but it is very unlikely the one I buy will come with a maf. does my 98 2v share the same maf that the 98 cobra uses? or should I put one in thats made for a cobra.

edit-oh yeah, its been almost a week since I changed the o2 sensor, and reset the codes, and the cel still hasn't come back on. not even for my o/r pipe

 

[crazynorwegian]

ttt

 

[Rekokulous]

Almost positive you can use a cobra MAF on a GT.

 

[Dan_Soprano]

Almost positive you can use a cobra MAF on a GT.

if you get it cal'ed for the 19# injectors you can. Try changing the rest of your 02 Sensors.

 

[Kilgore Trout]

Why not try cleaning the MAF. Instructions at www.bullittarchive.com... Don't cost nothin to try it...

 

[CanadaStang]

You can test your MAF sensor with a digital volt meter. With the engine running test the red [pwr]wire and the black[labeled A and B on the sensor connector], it should read at least 10.5 volts. Then measure between the other 2 wires[C and D], it should read between .34-1.96 volts. It's not the most accurate way of testing but it should give you a good idea. The best way is to test the voltage between C and D while the car is moving, but you'd have to hook up long lead wires to the DVOM meter and moniter the voltage as you're driving but that can be tricky to do .You can also unplug the sub connector instead of probing the wires and test the voltage there.It's mounted on the back of the shock tower shock on the firewall side. The wires should be red,black and white w/black stripe and yellow w/white stripe.

 

[crazynorwegian]

alright, so today I cleaned my maf real well with some electric cleaner, then I swapped the one front o2 sensor I didn't replace with one from the back. still no change. then I got the idea to play with the timing. I first brought it back to stock at 10? this made the missing worse. then I kept advancing it till I heard it knock. but it never started knocking. I have it set at 18? now, it has noticeably more power, and less missing, but the car barley idles. its more of a jerky missfire when the I'm lightly accelerating. when I floor it its more of a lack of power, but I hear a farting sound out of the exhaust. I had the maf unplugged for a while, I noticed that the car had no torque under 2000 rpms, and was difficult to accelerate from a stop without stalling it. but above 2000rpms it drives the same as if it was plugged in. I'm starting to get tired of all this and I'm thinking about just taking the car into for so they can do a full diagnostic.