Idle issues 1990 Bronco II

[holeshot]

I am having idle issues on my Bronco II. 1990, 2.9 V6, auto. Took it to the shop to figure out what is causing it to have a rough idle. It almost seems like its misfiring or something because the engine starts to shake when it hits the rough idle. Its hard to explain, but it runs fine when I'm driving, doesnt miss or anything, but only at idle there are issues. The best I can compare it to is it sounds like it has a big rowdy cam in it. lol. It runs great, then kinda lopes around, then back to running great at idle. Another thing is when I put it in gear and blip the throttle, it dies. Other than that, it runs great. Its just annoying when I am wheeling and trying to go over things and hit the throttle and let off and it dies.

The place I took it to put a new idle air control valve on it and new throttle position sensor and its still doing this.

Any thoughts on what else it could be???

Thanks!

 

[holeshot]

I should add that I put all new plugs, wires, cap, rotor, and injectors last year. It ran great, but as of the last few months it has developed this rough idle.

Additionally, if I try to hold open the throttle by hand (at the throttle body) it will run great, but then stumble and the linkage is pushed back against my hand...then it will run great again. I cant hold it at a lower RPM above idle without it stumbling. But what is wierd is it doesnt miss out or stumble while driving down the road.

I am stumped.

 

[Nathan123]

You can always try cleaning the throttlebody.

 

[uscg10]

had the same prob. change the fuel filter and clean the throttle body. also run a can of seafoam to the gas. worked for mine