OK folks, got one that is stumping me.

1997 LT1 with A4

I've been getting a repetitive SES light fot P0172 which is rich bank 1. Started about 3 weeks and 1500 miles ago.
Power is definitely down. MPG is down by 2-3 per gallon.

I cannot sort out what the problem is.

*Fuel injectors are fine. They are a matched set and near new (SVO 24 lbs rated at 25 @ 40 psi) but I did swap side to side with no change. Even stuck the stockers back in with no change.
*The cat. looks good and I cannot find any exhaust leaks. Anyone have a spare exhaust manifold to downpipe stud? Busted one checking the cat and will likely have a leak soon....
*Swapped out the O2 sensor with no change.
*Searched for vacuum leaks (visual) and found the elbow to the PCV valve was cracked. Replaced w/no change.
*Spark plugs are correct and good. Wires are older Taylor Pros...
*Oil is fine - no gas in oil.
*Gas cap seals correctly.
*EGR system appears to be functioning correctly, including check valves at manifolds.

I just got my fuel pressure gauge back and will check fuel pressure as soon as time permits this week.

Additional SES and DTC -- one today for random multiple mis-fires (P0300)

Additional oddities - about 10 days ago the evaporative emissions system had a fit of some sort. The car reeked of gas from the evap cannister. I have yet to check this out beyond a visual inspection of hoses, etc. The problem went away by the end of the day. We were stuck away from home in slow traffic during one of the hotter days this month. There was also a haze on the rear bumper and wing from what I assume must have been exhaust residue.

I'm starting to wonder if the Opti-Crap may be having a problem. It's the only other thing I can think of that might affect only one bank of cylinders. Today's SES adds to that suspicion.

I am open to any suggestions or ideas! I am stuck driving it right now as my son killed my truck. It's driving me nutters!

 

Check the EGR valve

You know where it is at. they make cars do funny things. They Do not bother our cars any more

 

I will remove, uh, recheck it. I should have my garage back any day now.....I hope.

 

Well, it was not the EGR. This is frickin' pissing me off. Any other ideas?


Eeerrrrgh!

 

I'd try testing the resistance of those Taylor wires. You may have a brittle area that's arcing on the manifold somewhere, especially if they're older.

What about a sticky valve?

Mike

 

What, you mean one of these? www.eric-o.com/camaro/DSC00041.JPG

 

Gotta love that situation.... Was that yours?

Mike

 

Why yes, that looks slightly familiar.

Busted mine flush. It is almost drilled out, but had to hash it back together with lots of O2 safe RTV so I could drive it the next day. Oh joy!

 

Wires checked out OK but are next to replace when I go after replacing that busted exhaust stud. Have to drop that side exhaust to get at #7 anyway. Just trying to avoid throwing $$ at it needlessly.

Sticky valve? I don't think so, but who knows. My problem is due to recent vehicle situations I have not been able to just go after the problem. That has changed, so I'll be getting to leave it in the garage as long as it takes now.

Thanks for the suggestions!

 

Yeah that is my manifold lol. Now it is sitting in a cardboard box in the garage and I'm thinking I like the long tubes a lot better.