Car is running like crap...

[sman]

Got my car out a few weeks ago, driving it here and there. An issue I really had hoped would go away while it sat on the lift all winter, magically did not....

Towards the end of last season the car started loosing its street manners. Hunting for an idle after coming to a stop, nearly stalling trying to stop (violently hunts for an idle, sometimes it dies, others its saves itself). Parking lots are a nightmare, constantly taking it in and out of drive to keep it from dieing, SUPER embarrassing. Usually quits once or twice at least trying to get out of my spot and on to the main road to head home after work. Turn the AC on and the problem easily gets 10x worse, it guaranteed 100% will stall every time you come to a stop or let off the gas while the converter is unlocked.

Just cruising down the road, no problem. Straight as a pin, no hiccups, zero issues.

9/10 times at WOT there are no issues, once in a while though I get codes P0131 and P0151, but these only occur @ WOT.

Do I have a fueling issue or an o2 sensor issue? This has really made the car VERY un-enjoyable to drive. Sucks the fun out of it.

Thoughts on where to start on this??

[c0ncEpT]

Do you have a K&N? Clean the MAF.

[99SSRhodes]

Both yours codes are pos #1 ho2s low voltage codes, doubtful both sensors are bad those can cause rough idle. When the car is cold and in open loop does it run fine? If it's rough cold and hot then not ho2s related. Maf will definitely also cause this unplug it when it's acting up and see if smooths out.

[1BADAIR]

If those are the codes I think they are it's power for the 02's and maf. Check the PCM sens? Fuse i think

[sman]

Just a paper filter, but its been a good while since ive cleaned the MAF. Ill put that on my to-do.

Will check the PCM fuse as well, but I only seem to get those codes (read: the SES light trips) only on a WOT run.

Generally speaking, it runs BEST, 60-90 seconds after I start it (cold start), where its found idle, got its bearings etc. Then after that minute or 2 window, its a complete pain in the ass. Its absolute WORST is right after a warm start, like I went into the store, came out, hopped in, start it and try to leave, id put $100 on it stalling at least once before I get out of the parking lot (although Im getting good at knowing when its coming and pulling it out of gear and hitting the gas real quick, then I can put it back in gear). After its good and warm it goes back to its normal scheme of only being a real pain at stop lights and such. But after a warm start sometimes just holding the brake and putting it in gear will kill it, like instantly.

[sman]

Interesting tid bit I forgot to mention. If im rolling up to a light and its huting all over for an idle surging. If I stop, fairly quickly, come to a COMPLETE stop, it goes back to a perfect idle, everytime. Like clock work. 1mph and it buck around so much it will give you whip lash, 0 and its perfect.

[99SSRhodes]

It's fuse #10 PCM sens but if it was blown your o2 codes would be current fail at key on along with low voltage maf map and iat codes. From what your saying sound like ho2s issue when it kicks into closed loop causing fuel trim issue due to faulty o2 data.

[99SSRhodes]

That could also be iac valve dirty or sticking pull it and clean it out. Also pull hard on the wires individually right at the connector base of the valve see them all the time broken under the conduit causing poor connection. What kind of tune did you have done to PCM?

[sman]

Dr Phil did the tune. I'll pull the IAC tomorrow and see how it looks.

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[1BADAIR]

What are your long term fuel trims

[nascarnate326]

Im guessing MAF.

[s.reef]

My guess would be MAF as well

[sman]

What are your long term fuel trims

Dont have them. Phil turned them off.

[meissen]

If unplugging the MAF doesn't help, do you have any way to data log? Would be the easiest way to see what exactly is going on.