new motor problems

[bamabaja]

4 months ago I had the dealership put a new motor in my 05 baja. They can't seem to pinpoint the reason it idles really rough. They said at one point the catalytic converter was glowing hot. I was thinking it could be going bad constricting air flow. Anybody got any ideas what could be wrong. I'm at wits end with the dealership.

[Scrappy-Doo]

If the dealership acquired the "new" motor for you then they own the problem.

If it's a Subaru dealership then they had better prove their technical worth and solve this for you or give you back your $$$.

Was the ECU cleared with the new motor?

If the catalytic converter is bad then...

[TastyHuman]

Just some Ideas.

Pull plug wires one at a time to see if the rough idle is only on one cylinder. How old are plug wires?

Pull plugs and read them, do they all look the same? What do they look like. Make sure they are the right plugs for the engine with correct reach.

Spray carb cleaner around intake manifold gaskets, does the idle speed change? If so... vacuum leak.

Pull brake vacuum booster hose off it's port and plug the port. Did the idle smooth out? If so... bad booster.

Clean/Test injectors.

[anarchy1024]

What would happen if an injector was stuck (partially) open? Could too much fuel be sent into the cylinder, which wouldn't be burned due to insufficient air, and then go to the catalytic converter where it would consume the unburned fuel and get even hotter? I don't know...