I helped out with the replacement of a head gasket (I have done several on my own caravan and other cars). The owner kinda failed finishing up the project so I am trying to get it done, so here is the problem:

The engine starts up fine but it sounds like it has a misfire. The idle tends to shutter every few seconds. I checked the spark plug wires and they seem to be on fine. There are no leaks, and I replaced the EGR vacuum line as it was broken.

I am thinking:
- Spark plug
- Spark plug wire
- Missing connector (there is a 4-pin grey connector behind the intake that is not connected to anything)
- Internal engine failure (strange as the idle sounds ok minus the misfire)

Thanks!

 

Got the wire color IDs on that wayward connector? The Idle Air Control (IAC) valve has a 4 pin connector. It's at the top of the throttle body. You should see a check engine light.