littletxfarm

Here is what happened. Truck (1999 GMC suburban K1500) has been great. 125,000 miles on it. Driving home fram church, felt a couple misses, check engine light came on. Missing got worse and I barely made it home, cause it didn't want to idle. Once it died in the driveway it wouldn't start back up. Starting wasn't normal either. It would hit, then drown out, then hit again.. Starting was strong them weak, then strong again.. Didn't seem to be firing right.

I went and got a code tester, and pulled two of these codes. P0300 - (Random Multiple Cylinder Misfire).. I looked this code up, and found it could be many things, although because the thing won't even start.. I am thinking it is a magor issue, and not a plug wire or disributer cap. I changed the Cam Position Sensor, which got the truck started, and it idled, but missed when given gas.. after turning it off, and trying another restart.. it went back to the up and down starting, and "not" cranking up again. So the Cam Sensor didn't fix the problem.. I am thinking now it is the computer, because of the way it happened, and how serious the problem seems to be.

Anyone ran into this? What should I check now? Any help is appreciated!!

RonH

Have you checked the fuel pressure? Low pressure from the fuel pump or stopped up fuel filter could cause sympoms you are experiencing. Maybe it's starving instead of drowning.

ZX1100F1

The ECM is very reliable and would be the last thing that I would suspect, it will also generally throw a code if it malfunctions.
Go with Ron on this one.