2003 Dodge Neon SXT 2.0L automatic 133k mi
When the engine is hot and in gear a low idle happens and shakes the car a bit. Keeping the fan on low keeps the RPMs a little higher but doesn't solve the issue.
Issue began during a coolant flush when the engine overheated after not bleeding the air out properly.
Head gasket has been replaced since.
No engine codes with bluedriver
Things fixed:
Air filter
IAC valve cleaned
Intake manifold gaskets
Spark plugs/wires
Valve cover gasket and seals
PCV changed
Oil cap changed
Tests done:
Makeshift smoke test
Pressurize system and spray possible leak points with soapy water
Battery disconnect and car discharge
Extra info:
Replaced all seals belts and tensioners into and out on the head gasket replacement. Head gasket blow was combustion gasses into cooling system that got topped off constantly until repair. Repair fixed coolant push out. Coolant cap replaced too.
I dont feel any positive pressure coming out of the oil cap
What other tests should I try or have I missed anything? I feel like ive hit plenty of the common causes but no major change.
Also tested fuel pressure and thats within spec.
Did a compression test and these are my results:
1 d147 too much oil
2 d141 w153
3 d146 w155
4 d140 w158
Will retest cyl 1 with better technique but the cylinder did increase in pressure
That sounds okay. They’re all near each other. I think the min is supposed to be 125psi. I think it’s time to take it to a professional independent mechanic & have them diagnose what’s going on, possibly using a scan tool to look at the live data. It may be worthwhile to look at the engine coolant temperature sensor too.
Have you already done a wet & dry compression test after the head gasket replacement?
Just to rule out the obvious, have you also cleaned the throttle? https://youtu.be/-PsP6ZBKZPE
Did a compression test and these are my results:
1 d147 too much oil
2 d141 w153
3 d146 w155
4 d140 w158
Will retest cyl 1 with better technique but the cylinder did increase in pressure
I guess some of the issue was my bad rtv exhaust manifold gasket. I replaced that with a real one and a lot of ticking noise went away. Only thing is that there still is some ticking when cold.
It runs a bit smoother but doesnt totally fix the idle drop and theres still a quiet ticking but idk how much of the noise is just the engine running