DrCreosote

Last week I repaired a burnt wiring harness to my O2 sensor and made my code 21 and code 43 go away. My bliss lasted only a few days when the car backfired when I started it. Since then, it won't idle. I can keep it running by messing with the gas pedal, but it is really gassy. One the road, it seems to run fine and has good (normal) power, I just hate stopping. When it first happened, my CEL came on, but when I started again later, no CEL. I looked under the hood to see if hoses or ducting were blown off in the backfire, but I couldn't see anything amiss. I might be using the wrong terminology when I say 'backfire'. When I tried to start the car, it seemed to cough and I could hear a muffled combustion sound under the hood. This has happened with this car only once before, and it separated my intake ducting, but at least that time it was an easy fix.

The vehicle is a 1990 4Runner, 3VZE (rebuilt 3 years ago) and an automatic transmission.

Any help is immensely appreciated.

DrCreosote

I tried cleaning the throttle body. It was kind of gunky, so I know it needed a good cleaning. However, it had no effect. Or at least no effect that I could discern. I could sure use some ideas, if anyone is even seeing my posts.