Engine missing at part throttle

[flash02]

My Runner seems to have developed a miss at part throttle, say 2k RPM's, never under a load, mainly while maintaining speed, say 30 mph in 3rd gear. Just looking for a place to start.

86 4Runner 22RE manual trans.

 

[essar5]

have checked for any codes?

 

[raevenzero]

AFM could have a rough spot that it could be getting stuck on. Happened to me and was tough to track down.

 

[flash02]

AFM could have a rough spot that it could be getting stuck on. Happened to me and was tough to track down.

Sorry been real busy....
Thanks for the suggestions, this problem or perhaps a new one, is getting worse, at times that is. Recently while under a load the engine will miss/stutter with some exhaust popping, let off the accelerator and problem is gone, back on stutter and popping, after a bit the problem resolves.

Too me this sounds like ignition/timing, and advance/retard problem?

 

[KLF]

How does the exhaust look? Very hot = running lean. Sooty exhaust = running rich.

Have you checked the plugs?

 

[flash02]

So I've not had any issues lately, I wonder would water in the fuel tank cause theses issues?

KLF, the exhaust looks good as do the plugs, 20mpg around town and 21-22 on the highway.

I'm leaning towards a AFM and or TPS issues also the fact that it is an 86' 4Runner with an old worked over wiring harness. ECU's don't take kindly to corrosion in old wires.