Conquest help...pleaseeee

[Vikki]

Hello. I'm looking for some advice about my 1986 Plymouth Conquest (sister car Mitz Starion). Hubby has tried, but really doesn't know where to start and isn't much help.

Here's what it's doing:

When I'm idling, like at a stop light or driving slowly as in a parking lot, then it 'surges' . The RPM's go up to around 3K and then quickly fall back down to around 1.5 or so. It does this repeatedly, and increasingly faster, until I'm back up to speed. On two occasions it backfired. It mostly does this when it's warmed up, although sometimes it will do it when cold.

Most recently it's started not even idling down in the first place. When I push the clutch, then the RPM's (again) go up to 3K and will pretty much stay there. I can cruise at 35mph without touching the pedal. We've replaced the injectors, which were leaking. It smells better (haha) but it still didn't fix the problem. I'm told it needs a mass airflow sensor but it's a rather expensive part and so we haven't replaced that yet. Any other suggestions out there?

One more thing: Most of the time the turbo works just fine, but there have been a few times that it ran very rough when the vacuum guage got up to zero. A few weeks ago I saw a thread in here that sounded just like this and the person described it as feeling like an inexperienced driver learning how to drive a stick. He apparently received some good advice and fixed his problem, but now I can't find that thread.

Does anyone know what causes these problems and how to fix them? Any suggestions would be greatly appreciated.

Thank you.

[moparmike70]

Sounds like you have a vaccum leak somewhere. Start by looking around the engine for any dryrotted vaccum lines or any that may have disconnected. Also check the air intake boot between the mas air sensor and intake for any rips or cracks that could possibly cause an air leak, make sure the clamps on each end are tight too. If this doesn't work start the car and let it idle (don't do this with the engine to hot as it could start a fire, usee your best judgement) spray some carb cleaner or brake cleaner around the intake gasket and vaccum lines and listen for the idle to change, it should idle up at first then idle down when you spray the problem area. This will help you pinpoint the leak and repair it.

[Vikki]

Thank you =) I'll suggest that to hubby.