seeking list knowledge - poor running 88 5ktqa

Livolsi, Stephane Stephane.Livolsi at
Tue Mar 30 14:07:15 EST 2004

Thanks Brendan.  
I'm sorry all, I did forget to mention that the O2 sensor is fairly new
(installed in the 86 last summer and swapped into the 88 last fall)

But..I will check as per your suggestion.  If the exhaust is so sooty,
then probably the o2 sensor is as well and not functioning as you state.
At least it shouldn't be too hard to remove, since I only did it a few
months ago....right....right....

> -----Original Message-----
> From: Brendan K. Walsh [mailto:bkwalsh4201 at] 
> Sent: March 30, 2004 10:51 AM
> To: Livolsi, Stephane
> Subject: Re: seeking list knowledge - poor running 88 5ktqa
> Sounds like an O2 sensor, check the dpr also. If your O2 is 
> fouled the ecu may thinks it's running lean and over 
> compensate, hence the heavy exhaust, black soot etc... 
> regards and good luck! Brendan
> "If God had intended us to walk he wouldn't have invented 
> roller skates." Gene Wilder, Willy Wonka and The Chocolate Factory.
> ----- Original Message -----
> From: "Livolsi, Stephane" <Stephane.Livolsi at>
> To: "Audi Quattro List" <quattro at>
> Sent: Tuesday, March 30, 2004 12:22 PM
> Subject: seeking list knowledge - poor running 88 5ktqa
> Hello all, needing your help (again).
> My 88 5kcstq (MC1 engine) is really starting to act up on me 
> and I don't know why.....
> Symptoms:
> 1.  The biggest is hesitation and misfiring, especially under 
> load. Started a couple weeks ago when accelerating in 2nd 
> gear between 2-3k rpm, it feels like something is cutting 
> out.  Now it's gotten really bad and even in first gear 
> starting off from a stop I cut some chugging and cutting out. 
>  Seems less noticeable/evident at higher rpm - ie, I rev up 
> to 4500 rpm and start off, there is less chugging if I keep 
> the rpm up there.  So the missing/cutout seems to be 
> boost/rpm related.
> 2.  Exhaust is stinky.  Not in a rotten egg way, but in a 
> heavy exhaust smell way.
> 3.  Black soot on the inside of tailpipe, and black soot on 
> the ground if I idle in 1 place too long.
> 4.  Engine seems to warm up a lot quicker than it used to.  
> Outside temps are admittedly warmer (+10C this morning - 
> woohoo!) but still seems to be getting up to quicker than 
> last spring/summer.  (engine working harder?)
> 5.  When it was colder in AM (couple weeks ago), it started 
> off almost on the first crank, would idle nice for a few 
> seconds then idle would die down and running would become 
> very rough to where it seemed like only 2 or 3 cylinders were 
> firing.  Upon restart, it wouldn't immediately idle but I 
> could keep it going with part throttle application, but the 
> running was very rough.  After 1-2 minutes of this, it would 
> idle on it's own ok and reasonably smooth.
> 6.  Now when I start in AM it will not start without throttle 
> application and I have to keep giving it throttle to keep it 
> idling for the first minute or so.
> 7.  When I decelerate (ie from 4000 rpm - push in clutch and lift off
> gas) the rpm will drop steadily down to about 300 then bounce 
> back up to about 750 where it will stay.
> My other car (86 5ktq) was running very well before I parked 
> it (the 88 is the nicer of the 2 cosmetically) so I have a 
> source of known good used parts.  So far I have taken the 
> spark plugs and wires off the86 and put them on the 88 
> patient.  No improvement and possibly even worse running. 
> Also the fuel pump is a 1 year old Pierburg and the ISV is 
> also off the 86 car which was working well.
> The way this came on, I am suspecting something that is 
> gradually deteriorating and getting worse.  But what would 
> cause these symptoms. What would cut out under acceleration 
> at low rpm?
> Any ideas gratefully appreciated.  I have looked at the SJM 
> site and other resources - just looking for some additional 
> input, maybe somebody else's BTDT.
> Stephane

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