Join Date: Nov 2009
Location: Clarendon Hills, IL
5.7 TBI barely idles, stalls in gear, runs and starts ok at part/full throttle
I'm helping a friend get his 92 Buick Roadmaster wagon ready to sell. It has a 5.7 Tbi with 190k on the clock. We were cleaning out the car as his daughter was not very tidy and the interior was a complete mess. We were also fixing some minor odd and ends, fixing the hood release, re-gluing some carpet, ect. I couldn't believe how big the back is with the seats folded down! Well Friday it started up with no problem, idled at about 1000 rpm when it first started then evened out about 800 rpm. So Friday the engine is good and sounds real nice.
Well I came over today to take some pictures and it ran like crap. It wouldn't start at all unless you held down the gas then the second you let off it stalled. I thought maybe it was low on gas (1/8 of a tank) so I add some gas from a gas can. It didn't help. I managed to get the engine idling if came of the gas very slowly but it idled unsteadily at about 400-600 rpm. The exhaust smelled very rich. When I put it into gear it dies. If I let off the gas quickly it dies. The odd thing is if I give it just a little gas maybe a little as 5% the "idle" stabilizes and if give it part/full throttle the engine runs fine. I checked under the hood no vacuum lines or plugs were disconnected but the snorkel to air box is missing. I didn't hear a hiss of a disconnected vacuum line at idle. I checked the air filter and ran it briefly w/o the air filter no change. There is no check engine light.
I'm guessing a vacuum leak but I'm not sure. The only other variable I can think of is it was about 10 degrees cooler today 39F. So what do you guys think? How should I start pinpointing the problem. Also keep in mind the budget for repairs will be limited.
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