so just did the head gasket/timing/dizzy timing.

car was running perfectly fine for not having an 02 sensor.

after about 150miles of driving this problem is occurring.

now it bounces between 200-750rpms after like 15 seconds of idling.

 

Whoops, was signed in under neil's.

Its my 240 that is undergoing this problem.

 

Check for vacuum leaks and plug your O2 sensor in.

Check your ignition timing, you might be off a tooth.

 

I'm pretty sure timing is correct, but should i retard or advance it?

The guy i got the car from welded the 02 plug closed?

i have positive crankcase pressure if that makes a difference?

 

Dude, you need to get an o2 sensor bung put on. Or buy my stock header and plug one in.

Your crank case pressure has nothing to do with it.

 

You could be off either way, thats what a timing gun is for.

Get a vacuum gauge and check to see intake manifold has a leak

And get an o2 sensor on it.

 

you tell me you have a stock manifold after i leave your house?!?

the problem was fixed after installing a real intake pipe and being able to plug in all the vacuum lines.