Hey everyone. Super new to this so I hope I'm in the right place. I have an e30 318is and I keep having a backfiring/hesitation when under heavy acceleration. I replace the cps, checked for all vacuums leaks, cleaned the air flow meter. I replaced with a known working iac, kinda stumped atm. I don't know if I should start look towards fuel pump. Fuel pressure regulator seems good. I'm just out of ideas.