when I take my foot off the gas and the revs drop down to tick over, they are dropping too far and you can hear the engine is about to stall but just in time it kicks in and settles back to tick over. Appears to tick over ok. It revs ok so I don't think I'm running on 3 cylinders.

Any ideas? I do have an engine light on and not found the code yet, so that issue may be related.

 

If you were running on 3 cylinders, it wouldn't go above 70mph.

But yes get that check engine light code pulled out. Go to auto zone or advance auto.

 

He mostly doesn't have an Advance Autoparts near him but yes, the CEL should be taken care of first.

Op, there are a lot of threads on S2ki about engines almost stalling when they are setting down to idle rpm after the owner lets off the throttle. Search around a little and you find lots of info. Most fixes for this problem involve dissasembly and cleaning of components on the intake manifold.