I'd like some help, please. I know a little about my Volvo, and I think it is really cool, but I have a question.

I have these symptoms in my 240GL Volvo, made in 1989:

I was driving home late at night, and my car has been working fine for years. Then it broke down. Whenever I tried to drive away, it sort of choked and died.

I tried to work out what happened, and I realised that as long as selector was in P or N then it idled okay.

But when I moved the selector to R or to D, 2, or 1 then the idle went all 'lumpy' and any pressure on the gas pedal made him stall. If I moved the selector back to P or N then the gas pedal worked normally again (what I mean here is that pressing it just made the egine rev up). So I was stuck, and couldn't drive home.

I asked at the gas station but the attendant wouldn't come outside and when I said I was stuck he offered to call the police. Sheesh.

So I went back outside and started the car, and opened the hood, and I looked towards where the air goes from the front of the car into the engine, because it sounded like it was sort of choking when it stalled before. I saw that the air seemed to go along a black plastic sort of conduit about 5 inches in diameter. This conduit had an electrical plug going into it, and I just pressed down on this plug, to push it firmly into place, in case it was loose. Suddenly the idle speed went up just a little bit, and when I went around, jumped back inside, put the gear selector in D and pressed the gas, everything worked fine, and I was able to drive home.

Can someone tell me what happened? Should I get a mechanic to look at this? Do I need a new car? My boyfriend said he wasn't sure what it was.