frankvan

Lately the car has been accelerating in an odd way and I can't figure out what is going on. It accelerates normally in 1st and 2nd, all the way to redline. In 3rd gear it starts to stutter (timing feels off?) at around 4000 rpm when at WOT. It does the same in 4th and 5th albeit at lower rpms respectively. It actually seems more speed related than engine rpm related as it happens as the car reaches 60-ish mph (or possibly higher, but can't admit to driving that fast in a public forum ).

The only thing I've done since I've noticed this is a valve adjustment a couple of months ago.

springer3

Sounds like fuel starvation. You are using high power for longer periods as you move to higher gears, and the fuel pressure may be decaying because the pump is not keeping up with the demand. There are connections for testing pressure and flow on each fuel rail. Even the cheap "FI service kits" have the 964 fittings. Clogged fuel filter, bad fuel pump, or intermittent DME relay could be the culprit.

Good luck