Hi I have a 1986 f150 xl 302 efi recently I have had my RpMs surgig and my truck will die. It doesnt have a problem if I'm on the throttle. I have also been getting very bad gas millage hardly even 5 miles per gallon if I baby it. Any ideas on what could be the problem would be greatly appreciated I have also put in all new fuel pumps and changed my fuel filter and did a new cold air intake and ran fuel treatments to see if I had clogged injectors

 

Pull your codes.

 

What was your reasoning on the Cold Air Intake ? Did marketing wrangle you in ?

 

What kind of fuel delivery system did you install? Factory or aftermarket electric pumps? What kind of intake (mods)? Who did the installation?

So, you're saying you - or somebody - changed the fuel delivery & air intake systems on a computer-controlled engine, but now it's not running right and gets 5 MPG and now the computer's not happy... shocking....

 

Lots of things can cause this, but like he said, pull the codes, start there and report back..

 

Sorry it took soong for a reply i pulled the codes and came up with EGR and cylinder 1 I replaced the egr and that fixed my gas millage and I adjusted my idle Rpm and I believe that fixed my other problem

 

Glad you're making headway.

The EGRs in these antiques are usually an issue, mostly sticking a bit open, not sure how they cause high mileage. There are 5 EGR position sensor Codes 31 thru 35 & EGR solenoid Codes; 83 or 84.

There are no codes for cylinders in 1986, so it may be something else. Next time you are on, list your codes out here.

When you run the diagnostics and no faults are found, you will receive a Code; 11.