Help with driveability problem!

[AutoSHO]

Hello all. I have been battling a throttle response/general driveability problem for the last 3 months (ever since I got the car) Here's the problems:
(1) The car takes approximately 1 second to respond to any throttle input. It I tap the gas, the revs will rise immediately maybe 50-100 rpms, and then about a second later the computer reacts and the revs increase.
(2) If I rev the engine up just slightly from idle (~2000 rpms) when it returns to idle it very nearly stalls (<500 rpms), then revs up to about 1100, then drops to 600, then up, down, and then smooths out. Tap the gas and the process starts over again.

What I have done to correct it:
Put in stock 55mm MAF. Changed slightly, but didnt fix anything. Bought a known working 55mm MAF from a parts car. No change. Bought a new TPS, no change. Bought another new TPS, still no change. No oil in the wells. 60K'd on time. Intake manifold is clean. I dont know where to proceed from here. Anyone experienced this before? Hints? Suggestions? Thanks for any help!

 

[93nighthawk]

Have you tried resetting the computer per sdpatt procedure? You second problem sounds like that, not a clue on the first, unless the ALT is not putting out enough juice.

 

[AutoSHO]

93nighthawk:
Have you tried resetting the computer per sdpatt procedure? You second problem sounds like that, not a clue on the first, unless the ALT is not putting out enough juice.

Yes. It does this regardless of whether I reset the computer or not. I have reset it numerous times to no avail. And it has about 14 volts, so the alternator isnt a problem.

On that note, however, would having the battery in the trunk cause any problems? It has a separate ground for the computer.

 

[AutoSHO]

Also, would bad Oxygen Sensors cause this? They threw codes, but I dont know if they are causing the code, or if they are simply reacting to some other problem the car is having. Thanks!

 

[twr]

The O2 sensors would not cause it. No codes at all, other than the O2's?? Almost sounds like a vacuum leak. Have you checked for that or low fuel pressure??

 

[AutoSHO]

twrsho:
The O2 sensors would not cause it. No codes at all, other than the O2's?? Almost sounds like a vacuum leak. Have you checked for that or low fuel pressure??

No codes other than the 02s. I was thinking it could be a vacuum leak, but them I would expect it to throw a lean code too. It only gives codes for HEGO indicates mixture rich (173 and 177 I think). It does this whether I have my A/F gauge connected or not. I'll check for vacuum leaks when I get home, at least where I can. The intake gaskets weren't perfect but they looked like they should seal just fine. Carb Cleaner here I come!

I haven't checked the fuel pressure. I suppose the Fuel Pressure Regulator could very well be bad. I'll check it out. Thanks for the help!

<small>[ November 25, 2002, 12:04 PM: Message edited by: AutoSHO ]</small>

 

[sdpatt]

If those were the actual EEC codes, they weren't caused by a vacuum leak. A vacuum leak would result in a lean condition from the intrusion of the unmetered air. Are you sure you are resetting the EEC? Are you disconnecting the computer keep alive memory lead or the entire battery? There is a sensor feeding the EEC a bad signal that is causing a rich condition. Were there any other codes?

 

[AutoSHO]

sdpatt:
If those were the actual EEC codes, they weren't caused by a vacuum leak. A vacuum leak would result in a lean condition from the intrusion of the unmetered air. Are you sure you are resetting the EEC? Are you disconnecting the computer keep alive memory lead or the entire battery? There is a sensor feeding the EEC a bad signal that is causing a rich condition. Were there any other codes?

I typically leave the car unplugged overnight when I reset the computer. Those were the codes I pulled Saturday. Left it unplugged until sunday, let it figure itself out (idle) and then, when I tapped the gas to start backing out (habit to tap it) it nearly stalled. The revs increase slightly, then a second later jump up some more, then it drops to ~500 rpms. Tries to recover, and jumps up and down a little bit more. Drove it after that and got a CEL both yesterday and this morning. I'll pull the codes again this afternoon, and I'm sure I know what they'll be.

On a side note, codes 173, 177, and 543 are the only ones I got. The 543 I am pretty sure came from one time when it flooded itself and wouldn't start until I held the pedal open. That was a one-time thing, however. I say this is where it came from because it didn't start the first turn of the key (nor the second) which I think would throw this code.

<small>[ November 25, 2002, 12:31 PM: Message edited by: AutoSHO ]</small>

 

[sdpatt]

Are you resetting the codes after you retreive them? Re-run the test and unplug the jumper while the codes are being displayed to reset the memory codes. This way you know they are the new codes.

 

[SHOtimer]

Just a thought, when I had my CE light on, which was throwing bad 02 codes my idle was horrible, and it would do exactly what you are describing, never died on me but would get really close. Just a thought,
Doug