Vacuum Check Valve

[newguy84]

I started mu 84 last night and it sorts stumbled and surged as it sometime will do (warm start) and it backfired... not real loud but it never backfired before. It sorta ran weird and had a fast idle. About 1200 rpm. This morning I checked for vacuum lines blown off and found that the line coming out of the check valve at the rear of the engine had blown off. This vac line come from a fitting at the top of what i think is the intake, and into the check valve. Two vac lines came out of the check valve it. One went to the round vac canister at the front of the car and the other very small one went under the distributor somewhere.

I plugged the line back in and the car ran better but still has an idle of about 1100 rpm.

2 questions i guess. 1, What may have caused the backfire and 2, could the backfire have ruined the check valve causing a fast idle

Any other suggestions of what i need to check would be helpfull.

 

[vetteboy86]

Sounds like you still might have a vacuum leak. I have experienced this type of thing before. The backfire was unburnt gas entering the exhaust, or so people have tried to explain that to me. Does the 84 have an electronically controlled advance?

Where in Indiana do you live. I am in the South Bend area.