94 4.0 starting, high idle, dieing issue..

[stl94ranger]

Just picked up a 94 with a 4.0 in it. Truck has 247,000 miles on it, and is in amazing shape. Anyway, it has a issue. When you start it, it revs to like 2500 rpm and slowly I mean slowly idles back down to around 1100 rpm. And then it will sit and idle at 1100 for a few seconds then it just dies..sometimes you can fire it back up and other times you have to go tap on the MAF meter before it will fire back up. Why would I have to hit the MAF meter? Also when you rev it up it revs up and it will stay at whatever rpm you reved it to for a few seconds before rpms come back down, but then the rpm comes down slowly..I just changed plugs with NGK platinum, and new ford wires...took off the IAC and sprayed it out with carb cleaner..cleaned up the MAF meter..and sprayed the throttle body with some carb cleaner..some gunk came out of there..not much though. Could I have a vacuum leak somewhere that would be causing this..Or do you think the Throttle position sensor coulg be bad? Or could the IAC be bad or the MAF??? Need help quick..

 

[twaranger]

I believe you are on the right track.The first thing I would check is the tps, maf, iac, and for vacuum leaks.....good luck, and keep us updated.

 

[matticus420]

try starting it letting it run and disconnect the map sensor the truck should stall out all most immediately if it stays on then Theres something else wrong
well thats wat my coworker/ my helping mechanic said

 

[LIMA BEAN]

http://www.therangerstation.com/tech_library/CleanMAF.html

Hope you didnt use carb cleaner on the MAF

 

[Field Ranger]

I have 96 and it has a similiar issue, I have unplugged the iac connection and that took care of the high idle issues I was having, only issue is you have to give it a bit of throttle on cold start ups. It did have a couple vac leaks that i fixed. To check for them I used cheap cigar, couple plastic bags to seal off intake and pcv and found the gasket on the iac was shot and the egr gasket was bad. Found another on the fuel vapor lines with carb cleaner. I talked with a Ford Tech and he figures the idle issue can be fixed with an ecm update.