Hey guys, I'm new here and also new to Ford Trucks. I have always been a Jeep guy.

A few weeks ago I found a really good deal on a 1990 F-150 2wd with a 300 Fuel Injected Straight 6 and 4 speed manual tranny (I LOVE THAT GRANNY 1st!!)

Anyways, the truck runs great and has plenty of power, but when its idling, there is a noticeable miss. (the engine shudders) I replaced the spark plugs (gapped them to specs), distributor cap, rotor, and put new cables. What else can I check?

In my knowledge of Jeeps, the 4.0 inline 6 is very prone to carbon buildup, but that is easily solved by reving the engine to 3500-4000 rpms a few times; you can actually see the stuff shooting out the exhaust pipe. Don't know if the same is true for the ford inline 6.

 

what plugs did you use?

if any brand platinums then that is your problem.

check for the correct ignition wire order, very easy to mess up.

i would not advise revving the heck out of the 300.

welcome to fte.

 

Used regular Motorcraft plugs -- I never buy into the hype of platinum or double platinum or any of that stuff -- I'm old school! LOL

First thing I re-checked was the ignition wire order, but its on fine. And I do tend to agree with you on revving the engine--somehow it dosen't feel like the 4.0 Jeep when you rev it up.

Any other help would be greatly appreciated.

 

when you said new cables, do you mean batt. cables or ignition wires?

 

Sorry, I meant ignition wires. I also put a new air filter in it. Next I'm going to grab a spray bottle and spray some water in the throttle body to see if that loosens up some carbon deposits.

 

take off throttle body and clean it with throttle body cleaner.

get a new gasket.

stop trying to use jeep tricks on fords.

use seafoam through the brake booster hose for a ford trick.

 

Allright, I'm gonna take off the throttle body and nail it with CRC. I have always heard to stay away from seafoam -- Do the ford trucks like it?

I have had jeeps all my life, so I know them inside and out, as well as all the tricks, so I figured that an I6 ford would behave the same as a 4.0 Jeep engine -- guess not.