Hey guys,

Having a slight idling issue. My truck will idle around 1500 rpm and not come down. I just installed a FMS MAF conversion kit and have not yet changed the firing order on the injectors. It runs fine, just not SEFI. When I did the swap, it was running fine and the idle was ok. That was about 2 weeks ago maybe. My spider/side gears went out and the truck spent about a week and 1/2..maybe 2 weeks sitting in the driveway until I could repair it. Got everything going and last night I test drove it. Now my idle is pegged on 1500 and won't go down on its own. Now I do throw a check engine light, but it's been doing that since I put the MAF kit in because of the injector order. So basically, everything was working ok after the MAF swap, but now its been sitting for a week or two and the idle is screwy. Any ideas?

 

Don't know how your engine is set up, but I have had (2) different occurrences of high idle caused by (2) different things. My '90 302 has all the emmissions control stuff on it. TAD, TAB, EGR EVR solenoids, smog pump and the whole nine yards. First high idle was the vacuum line coming off the bottom of the air bypass valve down by the smog pump. Second high idle was an Upper Intake Manifold gasket leak. First time idled at about 1100 and would not come down. Second time idled at about 2200 and would come down. First fix was easy, just put the line back on. Second one, had to install new gasket. The link below was posted on the 5 th, called High Idle Possible TPS? and I think it turned out to be intake gasket too.

Let us know,
guzzler96

https://www.ford-trucks.com/forums/s...d.php?t=225645 on manifold.

 

This might be a stupid ? Justin. Though you're throwing a check engine light for the injector order, have you run a code check again? You can get more than one code.

 

Thanks for the advise guys, but for some reason its fine now. Funny cuz right after I made this post I went out and it was fine....weird.

 

I see the problem was resolved, but what code is it throwing with the MAF computer?

 

TPS had a hickup.

 

Havn't checked it yet, but after the rain over the next few days i'll check.

 

I've had a high idle problem for a while. I checked for a vaccum leak and didn't find anything. I was looking it over today and found out that the "coffee can" loacted on the pass side fender under the hood, had a small rust out hole on the bottom. There is 2 vaccum lines going into it. I pulled one vaccum line and I had vaccum going into the "coffee can" but nothing going out. Then I found the hole in the under side of the "coffee can". Now the truck runs fine.

 

If the problem is solved then can I ask. This FMS MAF thing. Is this some cam change or what to change the firing order? Maybe a link to the site. You got me confused.

 

Do a search on MAF conversion

 

This is for mustanggt221, i was looking at the pics of your spark plug wires and noticed your air tubes going to the throttle body...where did you get these? i want a set of smooth ones so i can wrap thermal barrier tape around them and the airbox, but the set of tubes i have now are the stock ribbed ones...

 

They came in my MAF kit, but they are similar to the ones off an 87-91 or so truck.

 

It would appear that way. My '90 302 F150 has smooth ones. My '93 351 F250 has the ribbed ones.

Jason