Hello! I recently purchased a 87 RX. The only upgrade i have done to it was a 2 3/4 exhaust. When I excelerate i seem to be hitting some sort of fuel cut at around 3K and my car backfires...then it will start to ecelerate again it tries to climb through the RPM but around wont climb any higher than 4.5K rpms. I have no clue what can be doing this...at first I thought it was a bad O2 sensor so i disconected it. Still does the same garbage. My turbo is running on all stock with the wastegate connected. I have replaced the fuel pump two months ago. If anyone has any suggestions I am all ears. Thanks

Might try playing with the timing. I had an RX do that...turns out the timing was retarded too much.