S4 shudder
I'm going to bounce this one to the group. It has baffled me for a bit now. Car is an '87 S4. At full load in 4th gear on the track ONLY it has a shudder... it loses power then comes on, then loses power....
Cannot duplicate it on the street regardless of how hard we try! ONLY on the track. Have either checked or changed the following:
computers, flapper valve actuator, FPR, MAF, knock sensors, TPS, high flow pump.... I think that's it... Mark? Any ideas? It is getting frustrating and hard to do work on as we have to wait every month just for track days.
Would love to hear from others that may have had this and possibly solved it!
Thanks!
Markus
Cannot duplicate it on the street regardless of how hard we try! ONLY on the track. Have either checked or changed the following:
computers, flapper valve actuator, FPR, MAF, knock sensors, TPS, high flow pump.... I think that's it... Mark? Any ideas? It is getting frustrating and hard to do work on as we have to wait every month just for track days.
Would love to hear from others that may have had this and possibly solved it!
Thanks!
Markus
No indications on the gauges, dash, tach etc.... all appears normal...
It is a good one that's for sure! Wish we could figure this one out! Note this is ONLY at WOT on the track. Even on the highway at WOT, dragging the brake, this does not happen....
It is a good one that's for sure! Wish we could figure this one out! Note this is ONLY at WOT on the track. Even on the highway at WOT, dragging the brake, this does not happen....



