1995 318ti, m42, fresh top end/headgasket, new valve seals, lapped valves. All new vacuum lines, head shaved .010" to correct warpage from overheat when the Hg blew. New radiator, water pump, thermostat and coolant pipe (block). About 1000 miles since the engine went back in. Stock except for shielded K&N filter. 215,000 miles on the bottom end and other engine parts (MAF, DISA, injectors..etc)
She was running great, pulled strong all the way to redline until just the other day I noticed a big reduction in power. No difference in idle, nice and smooth. Labors to pull now past 4000 though..feels like I'm trying to punch thru if I keep going, whereas it used to sing all the way to 6800..in fact it was my favorite thing to do in 1st and 2nd
. The induction noise is also very loud, even revving by hand from idle. I have had this car for 4 yrs now and I never recall noticing that before. Very deep howl coming from the intake when pinning the throttle to the floor.
I'm wondering if the DISA flapper is jammed, and I'm being forced to stay on the short runners thru the higher rpms and that is why it is feeling so restricted.
My first thought was actually a bad exhaust leak, but looking under the car I dont see or feel anything, and like I said, the idle is smooth..no telltale puff puff sounds, or excessive exhaust odor from the front of the car.
No check engine lights either, but I'm going to do the key on 5 steps on the gas later today and check it just the same. I have dropped MPG though.. I keep a close eye on it and usually get about 25-26 and now getting in the 24s. I have slightly undersized tires also.. so the OBC is not totally accurate, but my #s were always consistent .
I'm stumped crew. And I miss REALLY driving my Ti... Any ideas?
1995 m42..not revving out..labors past 4000 rpm.. read on 
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