intermintant fault at 2500 revs

[neb_scot]

Since replacing the thermostat in the car, Ive been running with heat in the engine. As a result its been clearing itself out in there, from all the crap its built up while operating at low temps.

In the last few days Ive noticed a growing issue. As I accelerate or maintain speed the engine ticks over fine, but when I get close to or hit the 2500 revs mark it starts to not fire (nevermind mis-fire) and in the course of one second the rev counter will bottom out and then pick up again. Its almost like there is an electrical problem. However, if I continue accelerating, as soon as I hit 3000 rev, the problem has gone.

So it only presents itself in that small window of time, and and Im really confuwsed as to why. Any ideas?

[tekatlarge]

Just a wild shot in the dark but I would look at the throttle position sensor. It may have developed a bad spot that could be right at the RPM you mentioned. If ya know how to use an ohmmeter I would look real hard at the sensor going open at that point.