silver_rx7

Hi all,



Got this car for a year now. No updgrades, mostly stock. I have this problem, that engine revs surge +500rpm on each gear shifting. For example, if driving on 3rd gear at 3000rpm, and release gas pedal and press down clutch pedal to change gear, revs surge up to 3500rpm, and then slowly go down again within a second or two. It is like if I am pressing the gas pedal during gear shifting. Tested boost sensor, throttle position sensors and throttle cable, all fine. My suspect is a dirty fuel filter which is holding the fuel pressure high, and dampening the pressure regulator response. Any ideas? Also, when I first bought this car I had to flush the fuel in the tank, because it was backfiring when I accelerate under load over 3000rpm, possibly it was old dirty fuel. Backfiring had immediately disappeared after reflushing the tank, but filter might still be dirty.

JT-Imports

I have heard of the REVs dropping hard but not increasing.



What happens at a stop and you press in your clutch?

silver_rx7

On stop (when not driving) no surges occur. If I rev up to 3000rpm and press clutch pedal or release gas, revs behave normally. Problem comes in when driven under load, most obvious in 3rd and higher gears. Also sometimes needs extra cranking to start the engine when hot (about 7 seconds cranking max), I do not know if problem is related.