2.3L ('83-'97) 93 2.3l Consistent Misfire

[Ghost of Progress]

I posted about this problem before, but I figured I needed to repost with more accurate up to date symptoms because I am almost stumped.

A little over a week ago my truck started running rough like a misfire, I pulled over topped off on fluids and revved the engine and it seemed to no longer idle rough but still drove rough.
I have since installed a tachometer to see where it was idling at and it idles around 400 rpm and if I rev it anywhere near 2000 rpm it sounds like it is redlining. I originally thought the installation was incorrect but the truck decided to run right for a short drive around the block after I cleaned the IAC valve and when it did it Idled around 800 and the rpms seemed correct where I could shift comfortably around 3800 and get it up to 5000.

Since I got the truck I replaced the fuel pump, O2 sensor, Coolant temperature sensor, and all spark plugs and wires.

Since The problem started:
- Replaced the IAC valve (this was bad I had cleaned it three times in the troubleshooting process, the first two times the truck ran correctly for a short time the third time it did not but it was sticking anyway)
- Removed slack from my gas pedal (there was quite a bit)
- Replaced Fuel Filter
- Checked Fuel pump circuit (tested good and relay is good)
- Tested for leaking fuel injectors (floored pedal and tried to start, did not start)
- Checked fuel pressure which sits at 30 and jumps up when I unplug the regulator
- Tested vacuum first by smoke and then with a gauge, I do not remember what it sat at but I remember it was in specs
- Took off the ignition control module to get it tested, it tested good but I am not convinced

I have checked spark plugs and both plugs in cylinder one have buildup on them and are a little wet, so I unplugged both plugs to that cylinder and started it up with no change to the idle or rpm, tried the same on two and the truck didn't want to start so I know that cylinder one is the issue.

The things left I assume are that the fuel injector for cylinder 1 is not working properly or the ignition control module is bad.

If there is anything that I am missing please let me know.

 

[franklin2]

Does your model have sparkplug wires? If so, those and the sparkplugs are good on #1 cylinder? You could swap them with another to be sure.

You can also plug your timing light onto #1 cylinder wires and see if it blinks when you pull the trigger with the engine running.

 

[Ghost of Progress]

I figured out the issue, I replaced the ignition control module after verifying that the misfire didn't follow the plugs and wires, and now it is running properly, no more misfire.

So it seems like getting the icm tested at advance auto does not tell whether the icm is good.