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This may be unrelated, however did you try the O2 sensor? It made a huge difference on my 93 when I changed it, and you mentioned that white stuff in the exhaust. Could that be possibly from at one point burning antifreeze? Maybe coated the O2? Just things popping into my head. I would check fuel pressure, and have you checked for vacuum leaks?

A new o2 wouldn't be a bad idea, but I did swap it with another one when I had the rear manifold off. I have no idea of the miles/condition on the one I put in though. My o2 readings at idle are "5", but will go up to 900+ with a rev. I'd get a new one, but I don't want to drop $40+ on something that won't make a difference.

J Wikoff wrote:When I've had that problem it was vacuum leaks or wires.

Other possibilities are fuel supply, ICM, dirty MAF... I'm sure you've got spare coils you can try?

Ya, I've got about 3 spares of anything you can think of...

Gonna dig into it again tomorrow, had enough today.

Wow!! I would have sworn it was a value train noise and ended up looking in the salvage yards for a replacement.

Put my fuel guage on it this morning. Showing 45 at idle and 55-60 with high revs in gear (I'm not able to test WOT, but thats not where the problem is).

I finally got a CEL, P0171 - Fuel trim lean.

I don't get it... if I have ample pressure, why is it lean?

I'm gonna swap coils and ICM with the PA because I know its running good.

Vacuum leaks or bad 02.

maybe o2?

harofreak00 wrote:
I finally got a CEL, P0171 - Fuel trim lean.

I don't get it... if I have ample pressure, why is it lean?

Just a question, what about the injectors? Also...where does the fuel pressure gauge go? Cause maybe the regulator is bad? Just throwing ideas out there.

Would I want to be replacing just the upstream, or could the downstream be affecting it also?

downstream would really only tell you if the cat is not filtering right and has no play in poor running IIRC

do you mean o2's or something else?

Yes o2

a gearhead can correct me but from what i understand the rear 02 is only there to set the SES in case the cat isn't working,

also check the airbox i just found that my mechanic didn't put my accordian tube back on correctly and it's been sucking hot air and who knows what straight into the engine, i put it back together and presto! lost power returned and 34mpg hwy.

fuel filter could also be clogged slightly mine was when i changed it

Like said above, the rear O2 doesn't affect fueling.

Check the fuel pressure at idle with the vac line pulled off the FPR.

Wow John, you sure are right on in this thread. I went to go pull the vac line off the FPR and noticed a nice crack in it. I checked the other end of the line and it was cracked also.




At this point I decided to just replace all the vac lines to be sure. I went and got several feet of many different sizes. This is what I ended up with.



Here is what I replaced.


I also put in a new air filter just to be sure. I took it for a drive, instant improvement. It has power like an L67 should. It is still throwing CEL's for P0171 (lean) and P0172 (rich), so I'm assuming the o2 in there is bad. I am going to put the original back in place because it is the newer Denso style instead of the original AC Delco I put in there yesterday. I'll see if that changes anything and if not, I have 1 other sensor to try before buying a new one for $43 on rockauto.

Thanks to everyone for their help!

Glad to hear you got the power back

Some of those look kinda rough. Nice job! You're just about there

If it was lean before, and now it's rich, clear the codes and let it settle in.

I take back what I said about running like an L67 should. I drove the PA this afternoon and it has noticeably more power. The 97 still needs something, but I'm not sure. I replaced the original o2 back in and the o2 numbers look better and I'm not getting any CEL anymore.

fuel filter?

Talked to my dad again tonight. He says even though the rear of the cat looked OK, its very possible the front of the cat is plugged. When I get back from my weekend trip I'm going to pull the exhaust and take it around the block again. Its possible that the first time I did this, there were so many other runability issues that I couldn't tell the difference. If indeed the cat is plugged, I will probably just remove the guts from it and see if that fixes it.