hoping the gurus here could diagnose a problem.

I'm looking into buying a buddy's 90 240. Its been sitting in his garage since june 2007. After turning the engine over, with much initial sputtering and black exhaust, she started to idle just fine. But after trying to depress the throttle, it will spin up to about 1600rpm and then bottom out. if i hold the throttle in, it just undulates up and down between idle and 1600rpm.

what do you guys think it could be?

My first thought for limiting total RPM is a critter nest in the air intake tube, or possibly in the exhaust pipe. If it is in the exhaust, it must be made of mud or it would have blown out.

The drifting idle speed suggests that something is telling the idle air control valve to cycle. I have never understood the logic that controls the IAC, but I have seen it do some really wierd things when there are vacuum leaks or cracks in the air tubes.

I'm betting that if you dismantle the air inlet system, starting with the tube to the air cleaner, and ending at the IAC, checking for cracks and obstructions, you will find your problem.

yeah, the car has been garaged since june 2007 and hasn't been stared since.

stale gas could be an issue, should i siphon the gas out of the tank and refill it with a clean couple of gallons and a bottle of techron?

dont think its the AMM because i did the null value test and it died when i tried to go anymore than a "limp home".

It might as simple as Stale gas.

Could be a clogged injector.

It was running fine when it was pulled in back in June?
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'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.no.net/ebrox/Tony's%20cars.htm

Do a compression test and/or look at the plugs for clues