Calling all 1990 F150 experts!!!

[Jeff K]

If there are any Ford experts out there PM me.
Trying to get my son's truck running right.


It idles pretty good now but at cruise it miss fires awful. At WOT it's pretty strong, but when you let off to cruise the whole truck shudders, chugging.

I pulled the throttle body and IAC and cleaned the enormous amount of crap out of them. I replace both water temp sensors.

I did a compression test and all cyl are within 10# of each other at about 170

#2 cylinder had a dirty plug and even now doesn't seem to be contributing to the motor. Pull the wire and can't tell any difference. I replaced the plug and wire and no difference. Bad injector??

[tank_post142]

What engine?

[Michvalk]

Check the intake manifold for cracks/warpage. The 6 cyl inline motors have problems with that

[tank_post142]

if it is a 4.2 chances are you have a blown head gasket between #1 and #2 on the pass. side. it rarely will burn water but the compression travels between the two cylinders. my 97 e250 has this problem right now. don't think i'll fix it this time.

[Jess Tolbirt]

if it were a blown head gasket the compression wouldnt be right...if only one injector was bad i dont think you would notice it at crusing speed..check the EGR valve and clean it...

[Chrisj CMA]

If it is the inline 6.....mine was doing similar and I changed this and that cleaned it even ran half a bottle of seafoam through the master brake drum vacuum line (that goes diectly into the plennium) the seafoam helped a lot but it still wasnt right until I got a new computer.  That fixed it right up.  Computer was around $100 at a local parts house.

Hope that helps

[Jeff K]

Sorry, it's a 5.0

I was able to get to the injector with a 1/4 rod and listen, no clicky clicky. I put a meter on it and it was open.    $69 later and one new injector its fine now. 

And yes it HAD to be the hardest one to get to under the manifold.

[R J]

Jeff K, glad ya found it.   We have had several come through the kids shop and it was the injector(s).

We recommend to our customers to run a full can of SeaFoam every 4 or 5th tank of fuel in the winter.      Must work as none have come back.

Another secret is to keep that damn throttle body clean.    We usually just spray carb cleaner in it and wipe it out in the snout.

You must be the family mechanic like my son is.   Used to be both of us, but I retired from the job.    LOL.......   Still work when he gets swamped, like cold weather and big snow falls.   His snow plowing customers are always tearing up transfer cases, front axles and etc. so he does those and I and his SO do the little jobs.  She does the brake jobs and I do the rest.    Oh, she helps me a lot, she is also my wrench chaser, light holder, and just plain of Go Fur.

[Jeff K]

yeah, I pulled the TB and cleaned out all the muck. It has a 2 barrel TB the passage between them was plugged solid.

[Valkahuna]

Jeff,

I have a '92 F150, with the 5.0. I found this forum (see link) the best thing ever. Some real smart folks there with lot's of experience. Reminds me of the Tech Bard on VRCC. Just not the "family type" atmosphere.

http://www.ford-trucks.com/forums/forum28/