ok was driving today all of a sudden it started missing stumbling and would pickup speed but wouldn't go over 2500 rpm. changed fuel filter 2 weeks ago, checked fuel pressure key on/ no start 42 psi but while sitting bleed down to 35. running 35, if you rev and hold goes to 40 but drops back to 35 while still holding the pedal in the same place. running with vac line unhooked is 42. in my pump going or is it a fpr issue.also for some reason it started idleing at 2500.i cleaned iac and reset it now it idles normal still small miss and same pressure readings.

 

also now after sitting not running 30 min pressure has dropped to 28

 

what year and model? have you had it scanned for trouble codes? whats the gas gauge say, sure your not running out?