Code 43 has returned :(

While this is happening (misfires counting up), if you give it a slight bit of throttle, do the misfires go away?

Interesting you should ask. In fact they do. The misfires appear to be happening at "loaded" idle (idling in gear).

Checked/cleaned/replaced the Idle Air Control motor?

Not that I'm aware. Thanks for the tip. Will give it a try. This is beginning to drive me nuts.

Any tips for R&R ? Or is this a shop job?

I just went through a similar experience and found that one of my engine valves was running right at the end of the range of a hydraulic lifter and as the engine got hot stopped the exhaust valve from totally closing causing a misfire. Ended up taking that engine apart twice. The second time took .025 off the end of the valve and problem went away. Yes before I did this I replaced the Idle Air Control motor which didn't help at all. I also was going to replace the MAP sensor before I determined it might be a valve but didn't so saved that $50. After the second assembly I ended up with a tappet noise but found I had only installed it backwards so it didn't have chance to pump up. 5 weeks later I believe I might have an engine that will go another 75,000 before it will need much work.

Good luck, Ron

snipped-for-privacy@dodgecity.cc wrote:

Real simple - it's on the back of the throttle body. Two Torx screws and an electrical connector. While you're at it, just remove the whole throttle body (four bolts from the top, once you take the air cleaner off), strip off the IAC, the MAP sensor, and the TPS sensor (all remove the same - just a couple of screws), then give it a good thorough cleaning with some TB cleaner. When you put it back together, leave the IAC uninstalled. Plug the electrical in, and while holding it, have someone turn on the ignition (but don't start the truck - it will rev to redline!), and watch the movement of the IAC pintle. It should cycle all the way out, then all the way in, then settle to a position somewhere in the middle. This should all be smooth movements. If it's not, or if in doubt, you can try cleaning it as well, but a replacement isn't that much money, either.

Before embarking on this, pick up a new throttle body gasket - 50% chance you'll trash the old one while removing the TB.

Well, 100% chance of trashing the old TB gasket so your suggestion to pick up one paid off. Harder to get my ass up in there to reach everything than it was to R&R

Okay, all squeaky clean now. Had lots of carbon. Tried the IAC test OK. Reassembled, drove over to Autozone to have them clear the code. Darn thing coded again sitting in their parking lot idling. MIL lamp didn't come on but the code came up again on their scanner within 1 minute of restarting the engine. Trans in Park, idling w/AC on. Shut the eng off, cleared it again and restarted once more. Idling it comes backwithin a minute.

Cleared it again. Restarted the truck again and immediately kicked the idle up to 1500 RPM. Sat there 2+ minutes at 1500 rpm wasting $2.59/gal gas, all seemingly well. Let it idle back down and it gave a P0307 almost immediately.

What's next? Could the plug maybe be fouled again? This is beginning to get a little tiring.