My engine was rebuilt about 2 years/20,000 miles ago. It ran perfectly until a few weeks ago. All of a sudden, it developed an intermittent dead miss that I corrected with new plug wires. After that, the miss was gone, but the truck was still a little sluggish.

About two weeks later, the truck idled and cruised smoothly but started to miss again. Instead of a dead miss though, this miss only occured under acceleration - especially at low RPM's. In some cases, with larger amounts of throttle, it would backfire.

Last week, I replaced the plugs, cap, and rotor. All 8 plugs looked exactly the same with no evidence of any problems. I gave it two bottles of fuel system treatment. The cap had a pretty corroded contact and the rotor was worn so I replaced those.

Although the tune up has it idleing and cruising better, I'm still getting the same misses & backfires under acceleration that it had before last week's work. I don't think that it's a fuel system problem because if gas wasn't getting dumped into the cylinders, then there wouldn't be any be backfiring. Since this only happens when I give it more throttle, I'm suspecting that my timing is not advancing like it should under acceleration.

Since I have replaced all of the cheap & easy tune-up type components, is my next step to check the codes? I found the threads on checking codes, but where's the computer at?

 

One additional question: According to one artlce I found, EEC-IV wasn't used till 1991. Do I still follow the same procedures to get codes from my truck?

 

On my 88 302 F250 its located on the driver side above the fender well. Has a cap on it that says EEC Test. (Or something similar)

 

blu, did you test it the same way as described on this site? are the codes for yours the same as for EEC-IV?

 

Yep. Test it the same way.
Jumper with a file clip to give the signal to retrieve/send codes and use an analog voltmeter to read them. Its pretty straight forward after doing it once.

 

I have an 87 and would like to get the codes for my missing. How exactly do I do it ?
Actally I would just like to know how to get "the codes"


Daniel

p.s.

My truck sat for a year and one half and has all new plugs, wires and everything, I am assuming fuel filter.

 

I have an identical set of symptoms as originally described by wdj. My vehicle is an 89 F150 with 195,000km on the clock. I have done everything so far described in this thread. Has your fault been resolved yet?

Barry

 

To get codes: go to http://fordfuelinjection.com and click on "Getting Codes" on the left side of the screen.

 

if you have reas my thread it is almost like mine it turned out to be the EEC relay was bugging out. take out the relay and jump it with a wire drive it (not for a long time ) see if that helps

 

also check your fuel filter and pressure if its EFI should be around 40psi

 

Thanks Chris1978
I have had my problem for about 3 years. I sometimes get codes relating to the thermactor and EGR. I replace a few components and the codes go away but the miss remains. I will try your selay suggestion.

 

I have just changed the plugs, leads, fixed a vacuum leak, cleared all codes, fuel pressure ok, cleaned the idle speed valve, new air filter, etc. Still the same fault exactly as described by WDJ at the beginning of this thread. I can't email him to find out how he went as I am a new user. Does anybody know?

Barry

 

Click on the "Profile" link on the bottom line of his last post on this thread. You'll see an email link there.

 

I would like to contact wdj as the symptoms of his problem sound identical to mine. As I haven't yet placed 15 posts I cannot email him. Can anyone help please.

 

I have a 90 302 efi that is acting similar. it idles fine when its in gear it shakes,, enough to take notice and wonder what the heck is wrong now ,, but under full acceleration no miss. it shimmies at when i'm not hard on the gas. I'm guessing new wires roter and cap and quite possible a new coil. seems like it gets enough spark when the rpms are higher. I did put new plugs in it . 1500 miles ago