I know I have probably aggravated more people than I care to admit by responding with that line..."Just pull the Codes" but for cryin' out loud folks, this is the way you troubleshoot these trucks if they were made after about mid 1985!

If you are NEW here and/or your truck was made after mid 1985 and is stock (OEM) or fairly close and you know it, then assume that the first suggestion you will get from anyone here is "Pull the Codes". If you don't know how, there are MANY places to find out the procedures here, around the web, in books, from other Ford enthusiasts etc. The questions that have ANYTHING to do with performance, engine troubleshooting, "check engine" light no matter whether you think so or not, 99 times out of 100 running a KOEO and/or KOER diagnostic test will, at the very least, pinpoint a location to start troubleshooting.

Often I see folks get frustrated or worse, get no responses because instead of posting the question that says, "Hey, I got Code 31, how do I troubleshoot it?" the post will be, "Rough idle, poor throttle response where do I start?" Again, its engine/performance related so start with a KOEO (Key On Engine Off) diagnostic test. the engine doesn't even have to turn over to run this test. As long as there is a battery in the vehicle with enough charge to hold the computer's memory you can run this test. The KOER (Key On Engine Running) test will give far MORE information because the computer will have dynamic response information that it cannot get with the engine off.

"But GS92, I know the symptoms, why can't you just tell me what things to look at?" The short answer is, "Oh I can...so can many others... but there are so many possible causes for the symptoms that you could run through a half dozen "possibilities" before you actually hit on the real cause. Do you really want to waste all that time, energy, and potentially money sifting through a half-dozen possible causes before you get it fixed? I think not!

Like many of the older folks here, I grew up diagnosing engine problems by ear, by feel, by symptom. And it is a good baseline knowledge HOWEVER, when the vehicle you are trying to fix has "answers" stored in the onboard computer and you are trying to GUESS instead of just "asking" the vehicle, you are wasting your time, money and energy. Moreover, expecting us to answer your questions without having that information that is so readily available and time/energy/money saving is like asking the doctor to diagnose your illness without running any tests! You can walk in complaining of a belly ache but if the Dr. runs no tests, and just gives you an antacid and the real problem is appendicitis, you are still dead in about 12-18 hours!

In short folks, learn how to administer the KOEO and KOER tests and don't be afraid to run them on a regular basis. They will answer your questions before you have to sit here and wait for us to tell you, "Pull the Codes so we can better help you!"

Just a bit of editorializing from Greystreak.

 

You go man!