F150 300 six fast idle

1990 4x4 Tuff · #1 (**permalink**) 11-27-2008, 07:27 PM

Hi all new to the site I have a 1990 F150 4x4 new 300 six Gopher engine and have replaced all of the sensors. I had a very fast high idle now i have a slower fast idle. i did the propane test for vacuum leaks. Not sure where to go from here Thanks for the help.

Zip · #2 (**permalink**) 11-28-2008, 03:30 PM

Hey welcome to the site. While I cannot be of much help you should be able to get some good info from here.

http://www.ford-trucks.com/forums/forum28/
or here
http://www.ford-trucks.com/forums/forum52/

preppypyro · #3 (**permalink**) 11-29-2008, 09:46 AM

Did you check or replace your IAC? That seems to be a common problem.

My 89 has a 302, but I was having idle problems too, and I cleaned the IAC, and it helped. Mine needs to be replaced though.

1990 4x4 Tuff · #4 (**permalink**) 11-29-2008, 09:38 PM

Yes replaced IAC and all the rest of to sensors. Im thinging the person that did my engine did'nt torque my manifold in the rite order. when the engine is cold it works good, when the engine gets hot the pm go's up. Humm hot and cold expanison

preppypyro · #5 (**permalink**) 11-30-2008, 09:33 AM

I guess getting torque wrench and retorquing it would be a fairly easy job if you wanted to try that.

Not sure if you did already or not, but throw your problem in the 87-96 f150 forum, there are guys there that will be able to help ya fix it too.