I just bought a 1987 F150 2WD with an EFI Inline 6. The main problem with the truck was that it would die if running in park, once you put it in drive it would run fine. I figured I would start with a tune up since I didn't know when the last time I had one was and because the spark plugs were rusty. I replaced the Spark Plugs, Spark Plug wires, Rotor and CAP, Air filter, and Fuel line. I also ran some engine cleaner that the auto parts store recommended through the oil and gas. The PROBLEM is that now when accelerating the truck runs rough. It almost feels like its missing a cylinder. It feels like a slight rev then a loss of power in about half a second to 1 second intervals but not in any real order as in it will do this for a few seconds then stop for a few, when my truck gets warmed up it gets worse. So far I've checked and rechecked my spark plus, thair GAPS, spark plug wires, and firing order. The cap and Rotor seem to be installed fine. Is it possibly a fuel problem? Any help would be awesome! Thanks!

 

I meant Fuel Filter not fuel line LOL.

 

Pull codes before you throw any more parts at it without knowing what is wrong. The tune up probably didnt hurt though.

 

To read your CM codes or check for other types of codes and to run the self test go to one of these links below:

This is good for the KOEO test:
http://fordfuelinjection.com/?p=13

This one is good for the KOER test:
http://fordfuelinjection.com/?p=94
OR
http://www.broncodata.com/tech/codes.htm

Or get a code reader, here is a good one.
The EQUUS #3145
http://i54.photobucket.com/albums/g9...CodeReader.jpg

Also what was it you put in the oil and fuel tank?

 

I'll give the code thing a try thanks!

 

So I fuigured out that it was a faulty spark plug and now the truck is back to it's normal dieing in park thing. I ran the codes and i got
'MAP/BP sensor out of self test range". Is this a major problem. THanks for the info!

 

Yes but make sure it is plugged in and the vacuum line is OK going to it.
You may want to test it to see if it is OK.

 

What's the effects of this being bad? Any chance this is whats making my truck die in park? This is the beast! http://c1.ac-images.myspacecdn.com/i...cec5503738.jpg

 

It is possable that the MAP sensor is doing it.

 

Once again thanks for the help! One more question. How does one clear the codes from the computer? Thanks!

 

Also It took me a while to find the name of the stuff but it was seafoam that I put through the engine.

 

Start the self-test (ground the STI wire) and as soon as it starts the self-test stop the self-test (un-ground the the STI wire).
The codes in the CM should be gone.