struggling 5kcst

[Rokas Reipa]

Hi all. For the past month, I've been having a rather peculiar problem with my 86 5kcst(3sp a/t), namely that it struggles when accelerating on 80mph+ highway speeds. I remember the acceleration as being deliciously brutal at those speeds not too long ago, but now it's gone. The problem starts appearing at the upper 3000rpm range and continues all the way to the redline. It starts surging noticeably(feels like the ignition timing is being retarded) and the acceleration from 80 to 100 takes quite a while now. Here's what has been checked/replaced so far: New michelin man hose, new bosch super 3-electrode spark plugs, cleaned out the k&n air filter. I also took out and thoroughly cleaned the injectors(two of them were badly gunked up) and this helped noticeably but did not eradicate the problem. Error codes indicate a bad knock sensor but I somehow doubt this would be affecting the engine in such a dramatic way(Doesn't the knock sensor only retard timing by 7 degrees or so?). Also, the check-engine light doesn't always light up when accelerating, although it lights up often when the stock boost gauge exceeds .5 bar. BTW, when accelerating at WOT, the boost reaches 1.4 but it really doesn't feel that way with all the surging, etc. Is my problem a bad knock sensor or could it be something else? TIA for any help.

Rokas
1986 5kcst  151k and counting......
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.audifans.com/pipermail/quattro/attachments/20000901/02d1d97f/attachment.htm