IAC issues?

[Gregin30655]

Hey all, I have an 88 with a 2.9 I just bought. I noticed the idle fluctuation when I got it, but drove it from NC to GA with no issues (after topping off with gas in NC) then about 20 miles from home it seemed to stumble at low rpms and take off once it hits about 2500-3k rpm. It had sat for 6 months or so.....any ideas? Fuel filter clogged with sediment? Vacuum leak? IAC? I'm still showing over half a tank of gas so it isn't out but it sputtered and stalled almost like that.

 

[Curious Hound]

I’d put a New fuel filter On it and see if that fixes it. Have you changed other fluids and filters yet? Good idea when buying an older used vehicle. With an older 2.9l, a coolant system flush and refill might be a good idea. Never let a 2.9l overheat. Take very good care of the cooling system.

 

[RonD]

And don't discount "bad" gas, "on the road" fill ups can get you some fuel with a higher water content, which is what "bad gas" is
You can add a can of "octane boost" or similar ethanol additive, it can bond with the water so it can at least burn and exit the system without the major stumbling
Gasoline and water can't bond, so the water will cause misfires as it comes thru the system, usually noticed at lower RPMs because you simply feel it more

 

[Gregin30655]

I’d put a New fuel filter On it and see if that fixes it. Have you changed other fluids and filters yet? Good idea when buying an older used vehicle. With an older 2.9l, a coolant system flush and refill might be a good idea. Never let a 2.9l overheat. Take very good care of the cooling system.

Its sitting now with a dead battery, I guess I have an electrical pull on it too. So I'm going o go through it all. All fluids changed, and a good once over. It also has a leak that is on the front of the engine down low.