What should i check out?

[medicbearusaf]

Truck has always had a slightly rough idle... Sometimes perfectly smooth, sometimes stumbles a lil... Lately almost everytime i dont have my foot even slightly on the gas it wants to stumble and stall... As soon as it starts to fall under 800rpm but as long as my foot is slightly on the gas to keep it at 800 or higher its fine... been told to check out the throttle position sensor, maf sensor, or the idle air valve.. any tips or things to look at. esp since the cheapest i can find a IAC valve is 50$....

its a 95 4x4 4.0

[AllanD]

isn't 800 idle speed for a 4.0?

AD

[medicbearusaf]

thats the minimum i have to keep it at otherwise it starts to drop and bog out.... so i have to apply a lil pressure to keep it at that...

[MAKG]

I guess he has a stick.

You're lugging the engine. You're assuming slow revs = good mileage. That's wrong. It will also kill your engine. If you're under 2000 RPM, downshift. You can get away with 1500-2000 RPM on a 4.0L, but it will work better if you don't. 800 RPM under power is just ridiculous. My 250 I-6 will barely do that, and it has a 400 RPM idle.

[medicbearusaf]

oops sorry its an auto

[97ranger4x4]

MAKG, i think he meant 800 sitting at a stop light not driving, that is almost impossible to drive with the RPMS that low. I cant do it. My truck is happy around 25-2800 rpms it seems like. Above 3000 cruising and it drinks fuel

[abrush]

Did you look to make sure you don't have any vacuum leaks? If you have a cracked hose if could cause this. I would start there and see if you find anything before buying other parts.