Help Car Running Like #$**@)(#$*!!!

[grrrrrrr]

My car hesitates and backfires on medium throttle between approx. 1500 and 3000 rpms and pops when idling down the road with no throttle applied (rpm's up, no gas) At full throttle the problem isn't so pronounced, and there is no backfire or hesitation above 3000 rpms. During full throttle exceleration (I can't spell) the car drives okay, with no problems above 3000 rpm's, but when power shifting into second I noticed a louder than usual exhaust note as the clutch grabbed... Also, at very low throttle the car runs and drives fine. I pulled the codes and got these

KOEO (Key on Engine Off)
Stored:
327 = EGR Circuit below minimum voltage
332 = Insufficient EGR valve opening detected
543 + Fuel pump circuit open; Battery to PCM (what does this mean?)

KOER (Key on Engine Running)
313 = AIR not bypassed during KOER
314 = AIR system inoperative during KOER (Bank number 2 with dual heated oxygen sensors)
311 = AIR system inoperative during KOER (Bank number 1 with dual heated oxygen sensors)
What is this AIR system? and how do I fix it? I just replaced the o2 sensors about 3 months ago and I disconected the EGR on the way home today to see if that affected the problem (it didn't) so I'm pretty sure thats where the 327 code came from. The rest, I'm clueless on... Can someone help please?

None of these faults are consistent with the Hayne's manual diagnosis of the problem. I also had a fuel problem earlier. The retainer nut on the AFPR (kirban) came loose and I think the adjustment screw vibrated out a bit. I checked the fuel pressure before I screwed it down and it was sitting at 50psi with vacuum. I adjusted it down to 43 psi with vacuum (what the car ran best with on the dyno) and was hoping this would cure the problem. If anything, it made it worse... I also 5 days ago cleaned my air filter (K&N) and cleaned my MAF. I hope I didn't screw up the MAF but the car ran fine after I did this maintenance. Sorry for the lengthy post... but I need help...

 

[94TURBO5 O]

It helps most to work backwards to where the car was fine before. Something my wife taught me b/c lots of time I'll work on a specific part and then do something else and the car will run freaky. Try disconnecting the MAF and the battery (-) and inspect it again as well as the FPR to make sure it's not messed up. If parts are not installed properly then of course they will fail to operate correctly in the whole scheme of things. Make sure that you IAT is facing in the correct direction when your screw it in.

 

[grrrrrrr]

Alright thanks... I'll check all of that...

 

[94TURBO5 O]

Also try setting the fp to 40#s with the vac line OFFf and connect it back after the ajustment.

 

[grrrrrrr]

Okay, no change in status after trying these things, can anybody tell me what this AIR stuff is as pertains to codes 311, 313 and 314 in my original post. What is it supposed to be bypassing?

 

[dstanggt50]

I'm not 100% sure, but I think all of the 3xx codes are smog pump related, I'm not sure if that would cause your issue, I'm pretty sure a lot of people get those codes when they remove their smog pumps, I had the 327 egr code on mine, didn't really have driveability issues, but replaced the egr and evp and the code and check engine light went away.

 

[grrrrrrr]

Bump...

 

[grrrrrrr]

Bump again...