My 2003 Ranger with a 2.3L started off with a idle that would drop off and nearly stall. Code said mass air flow sensor so I tried cleaning it with no luck. After a new one it fixed the idle but the stumbling and backfiring started. Check Engine came back on and local parts store said map sensor. Changed that and only change is that the check engine light is off now. Still runs bad. When I was at auto store he disconnected mass air flow sensor and it ran much better but idle problem came back. So as of today, no check engine light but stumble with backfiring is still there. Any suggestions?

Thanks all.

 

PS: forgot to mention that I changed the coil pack as it had acted like this when the original one went out.

 

Oxygen sensor? Check that all ur plug wires r on correctly, and that they r attached to the correct spark plug.

 

Thanks man. I'll check it today.

 

They're all correct according to the order on the Motorcraft coil pack. Which Oxygen sensor would you replace, the upstream or the downstream?

Thanks man.

 

O2 sensor wouldn't cause that to stumble. It would run rich, but not that rich.

Try disconnecting the battery, and then pulling the harness off the ECU on the firewall. This should reset everything.

You may need to hold the throttle in for a short bit to let the truck re-learn idle.

If that doesn't help, then you may have further issues. You'll need to check TPS values, and make sure your fuel pump isn't dying. There are a lot of possibilities.

 

Thank you. I will try that as well. Do you happen to know where it's located?

EDIT: Nevermind, I found it.

 

Reset the ECU and changed the TPS and it still is very jerky and backfires. Bogs down as it's backfiring and won't accelerate for a bit. Also, has a odor that's coming in the cabin. Any ideas. Not sure if the check engine light is on or not (only took it for a short drive).

 

Just an update. My son changed out both O2 sensors and that took care of the bogging down and backfiring. Talked to a guy at parts store and he suggested cleaning the throttle valve and the idle air control valve. If that doesn't fix the jerky-ness, I'll replace the IACV. We'll see.