The 86 t-wagon I picked up will only run well once the turbo spools up. It idles ok, a little rough, but not bad. It misfires and stumbles when you're driving it untill the boost comes, then it runs nice and smooth and pulls pretty hard all the way through the redline alarm.

 

When I changed the oil, there was a lot of gasoline dilution. Like mabe an extra half-quart worth of gas mixed in. It had sat for 4-5 years before I got it, so i'm wondering if mabe an injector is leaking? Though I would think that would still cause problems under boost?

 

It's such a stark contrast between on and off boost engine behavior. Makes me think the pcm isn't seeing something it should be, and mabe thinks the engine is on boost all the time?

It could have really bad rings...

-Bill

Does it require premium gas?

I remember a post about "vintage gas":). I'd clean the entire fuel system. Pull the injectors, inspect, o-rings, so on and so forth.

 

"You don't need luck, if you're good".

i seafoam every car i get before i even try to diagnose it.in this case you would need to use a vacuum line from somewhere on the intake or go directly into the fuel line so that you can run through the injectors.yeah that would probably be better.

I agree with the Seafoam treatment, etc.

But if its running better at boost, you probably have a vac leak somewhere.

Get a can of ether and check all the intake hoses and around the base of the intake manifold.

You have at least one bad fuel injector.

While idling, pull the spark plug wires one at a time. When you pull a wire and "shut down" that cylinder, it the idle changes, gets worse, then that cylinder was fine. If you pull a plug wire and the idle DOES NOT change, you found the bad cylinder. That injector for that cylinder is bad.

Get a used one to get you by, but get new ones or have yours rebuilt later.

Take your time removing the old injector. Those little screws that hold them on break easily. Spray them with penetrating oil several times before you tear into it.

 

I had an 86 turbo three door that had the same thing wrong with it.

Good luck

you could also have a blown head gasket / cracked head causing low compression in a cylinder and when boost comes on it starts to fire again because you got compression again

The only thing that would cause gasoline dilution of the oil is leaking injectors.