I have a 87 F150 302 F.I. I bought it because it ran SO nice I knew the engine wouldn't give me any trouble. I've been using it mainly as a yard tractor only driving it 2 miles at a time to unload trash. For over a year it's smooth a silk. Last week I jumped in it and it started missing, popping like a lean pop if you gave it some gas. Running barely on 3 or 4 cylinders.

Not having worked on anything with a computer the only thing I could do was look at the dist., and plugs. Plugs were horrible. Changed those. But that didn't fix the problem. Checked all of the fuses. It's just odd that one day it's perfect then it's like it got a load of bad gas or something. Gas is ok BTW.

Is there any common weirdo problem on these 302's that cause this?

Thanks
Bruce
909-844-1081

 

"Is there any common weirdo problem on these 302's that cause this?"

Not a 302 specific problem but rather a FORD computer problem.

Click this link and do some reading.
A9x ECM's (and same years ECM's) Failures Due to Age

This may not be your problem, but it fits the definition of a "weirdo problem".
It's worth a check.

As per usual diagnosing, retrieve codes in both KOEO and KOER and report back.

Good Luck,

Bob

 

1. Pull the codes. I can not stress this enough.
2. FULL tune-up.
3. Check fuel pressure
4. Do a search on here. Loads of threads talk about similar problems, more than likely someone has had the same problem and dealt with it in a thread on this board.

If all of that leaves you empty handed then come back and give us more detail about what you're experiencing. If you have dual tanks try both and see if there is a difference. Does the truck run bad until it warms up, runs fine until it warms up, or all the time?

 

I got a deal on the truck because the previous owner had disconnected the rear tank and the main pump on the frame was dead. I replaced the main (high pressure) pump first and the filter 18 months ago. Ran like a dream until last week. Over night - right off the bat it won't idle. If I try to keep it running and give it a bit of a swift pump it'll backfire in the plenum. Trying to keep it running at low speeds doesn't work eiter. It pops right off every time you turn the key, but goes to rough idling immediately.

So, overnight from running perfect to 3, 4 cylinders firing. I've yet to check for fuel pressure. Getting a tester this week.

 

When you say "tester" do you mean code reader? You don't need one to pull the codes but it makes it simpler so I have one.

 

Fuel pressure tester. Thanks

 

But I don;t have a way to read codes so I'd certainly appreciate your help!

 

Alright I'll see if I can dig up the instructions for testing without a reader, but a reader is about $25. Totally worth it to me.

 

I agree. I must have one. Thanks. I'll post back later.

 

OK so do this.

How to read a check engine light code on a Ford 1983-1995 EEC 4 system - YouTube

 

Also, you said you changed the plugs and fuel filter. What about the wires, cap, and rotor?

 

Yes there is a valve on the driver side fuel rail. NO you cant use a tire pressure gauge.

 

I did changed the cap, rotor , wires.
Figured I need a OBD1 tool. Only ones I've seen are on Ebay. Are these decent. Anything to look for in a scan tool?

 

You don't NEED a scan tool. The video I posted tells you how to pull the codes without a tool. If you want a tool anyway I use this one:
Equus 3145 Ford Digital Code Reader : Amazon.com : Automotive

 

I just thought it'd be easier to read. Which it is right? I won't need a code book right?
(Thanks!)

PS - I thought I'd better reference this too - I changed the rear end because the truck was used to put boats in the Pacific and salt water had completely ruined the diff inside. Plugged the wire back in the top. But I wanted to mention this because the problem came up right after the rear end change.