Originally Posted by jimandpam
Well the check engine light came on the other day when I was driving to work. It started to idle realy bad and then the light came on. Went on in to work and when I came out to drive home the light stayed off and it ran fairly well for the 13 mile drive back.
I can only think of to run through the diagnostic procedues that I posted. That code will be a good hint. When the computer throws on the check engine light, it has seen an issue, and it stores the code in stored memory.
Need to pull codes. But the code could have been trigger by something else that's off, that is why I suggested to check your vitals; eg fuel pressure, vacuum, compression, etc. Could be a lot of different things, and it helps to narrow down by making sure that everything is where it needs to be.
Can spend hundreds replacing every sensor under the hood, when it could be a bad fuel pressure regulator; a fuel pressure gauge would have caught it right off the bat...
Look at the diagnostic connector on this page:
You'll want to jumper the small square plug to the terminal indicated on the connector as shown with a paper clip or short piece of wire.
Since you have a check engine light, all you will need to do is turn the key on 'Run' and watch the check engine light blink in the cab. Just did this on a '93 and the CEL was burnt out, so I hooked up a 12v test light and taped it to the hood in place of the meter..
Once the key is on run, it will blink sparatically for about 1 sec. This is the fast codes (disregard).
Then it will start pulsing out clodes in blinks. They will be 2 digit codes, with 11 being the OK code. Codes are repeated twice.
1....1..1..1........1....1..1..1.. for example this would be code 13.. Best to write down with a pen and paper while going through this.
Once it's gone through the first portion, there will just be ONE separator pulse. This indicates that the system is now outputting stored memory codes (the codes you need from the previous CEL).
Once you have gone though that, make the sure the engine is warm, and run though KOER. Basically leave the jumper connected and start the truck. It will do a series of tests and the idle will change. After about 30-45 sec. there will be a single pulse. This is called the goose pulse. Give the throttle a good wrap so that it can test the TPS sensor function. If you don't you'll get a no throttle reseponse detected code.
After that KOER codes are blinked out.
Also think that computer can do a cylinder balance test.