Rough Running 90q

[SJ]

How many miles do you have on the Oxygen sensor? Sounds like a funky sensor
to me. I wrote a post on how to test an oxygen sensor on the bench.

Vacuum leaks will usually cause hard starting.

Easy way to check for vacuum leaks is to remove the intake boot, Cover the
fuel distributor with plastic, put boot back on . .and blow air into the
intake system using one of the spare ports on the boot. If its not holding
pressure, you have a leak.
There are two designed-for vacuum leaks. One is the fuel injector air
shroud. The second is the PVC system on some models. Pinch off these hoses.
Turbo cars have more complicated plumbing that I dont know much about.

SJ
85 Dodge PU, D-250, 318, auto
85 Audi 4k - - sold but still on the road
88 Audi 5kq
90 Audi 100q


> From: "DePenning, Charles [EPM/MTN]"
> <Charles.DePenning at EmersonProcess.com>
> Subject: RE: Rough Running 90q
>
>  Well, I think I can scratch the cat off the list as possible problems to
my
> poor running 90q- this morning I took the cat off at the exhaust header
and
> started it up- same exact behavior as before.  Plus, the cat looked really
> good from the front anyway. This is driving me nuts- there are only so
many
> inputs to the equation to make the thing at least run decently...
>
> Bad OXS?
> Vacuum Leak?