my check engine light will come on as i am driving every now and than when the truck gets warm but when i get off the gas than get back on it. the light will go off. im not sure how to check the code on this truck tried lookin in my haynes book didnt help can someone help me by tellin how to check the engine codes?

 

Look next to your fuse box in the engine bay, there will be a diagnostic plug there. Turn engine off and jump the terminals it says in the book, then go inside your truck and turn the ignition on count the flashes the check engine light makes and then look them up in your book.

 

iSearch

 

ok i took this picture of these 2 plugs that were plugged into garmets on the driver side fender and im not sure which plug it is and how to jump it never done that look at the attachment for the two plugs

 

it should be right on the side of the fuse box.
some on may have written something on this probloem try searching it

 

tried searching it nothing at all nothing behind the fuse box can u post a picture of what yours looks like so i can see it

 

Those aren't the plugs... the FUSEBOX on the passenger (right hand) side of the engine bay. There will be a little cling-on port with a cover that says "DIAGNOSTIC" on it. She hangs off the fusebox like flies on feekle.

 

One on the left. And guys, hes got an 85 I assume from his name, and the picture he posted. Original poster, yours is going to be on the left, put a thing of speaker wire or even a paper clip in the 2 terminals. turn the ignition to "on" then count the flashes. Ill save you a little time and post a chart of your trouble codes. Courtesy Rodger Brown. Btw, Anyone ever care to actually read his page...?

 

Oh and Later models look like this... Image also courtesy of 4Crawler...

 

i got it thanks for info ok now engine code 5 o2 sensor here is my problem my muffler got a hole in the bottom so i cut my exhaust off before the muffler but still have the cat on could the o2 sensor gone bad since i have no muffler or what could cause it and have replace the exhaust yet

 

I really dont see why, did this happen like, right after you cut off the exhaust ?