Challenge for all you motorheads

Problem: The car stutters when I am between about 2500 and 4000 RPMs. I dont feel a power loss, so much as I think it might be misfiring every so often. It doesnt do it at WOT, and everything else seems fine. It idles fine. Also, it seems to do it less when my engine temp is where it normally runs. I just started having these problems since winter came around, but it was still doing it today, when the temperature was back to about 70 outside.
I replaced the plugs already, and reset the ECU in case there was some bad vibe going on in there. I did notice it started after I used some cheap stop-and-shop gas, so I have been using Mobil 93 since, but it hasnt helped any.

Let me know what you think it is, so I can start checking it out. Im afraid to drive it while its running so poorly. I was thinking maybe the fuel filter? Maybe worse off, the fuel pump? But it doesnt stutter at WOT, only at about half throttle.

:shrug: :shrug: :shrug:


injectors? i’d replace the fuel filter first because it is so easy and cheap to do.

Engine surges while holding accelerator steady

  • Intake air leak.
  • Fuel pump faulty.
  • Loose fuel injector wire harness connectors.
  • Defective ECU or information sensor.

I read the teg tips thing, but how would i go about checking these things? Is there anything short of replacing them altogether?
Importantly, how do i detect an intake air leak…or a defective ECU?

thanks in advance,