Hey, I'm still kind of new to the forum, but I just can't figure this out on my own and a true mechanic doesn't just throw parts at something. I have an '01, 223,000 on the clock, runs great, almost no rust (Keep in mind it lives in Missouri), but the CEL flashes at 3000 rpm, and stays on once it comes on. It doesn't store a code. If I have to stop, it'll die, and I have to crank it with my foot on the gas and neutral drop it. However, most of the time, it's happens getting up to interstate speeds, and I can drive it fine, may kind of run rough for... Like what, 30 seconds? And bam, normal except the cel. When I shut it off afterwards it doesn't store a code, it doesn't come on, and runs fine. It'll start up like it has 3,000 on the clock, not 223,000. So I honestly don't know what's going on. I replaced the maf on it because it went out, but otherwise... It's mint. Any ideas?

 

Some conditions do not set a code until it has occurred multiple times or the code can be cleared if it stops happening. I don't know what the rules are for storing misfire codes in these trucks. A flashing CEL means misfires and potential damage to the Cat Converter. Not all code readers are created equally, There are many threads here about good scanner capability for cheap that can give you the info that you need to diagnose complex issues.

1) The code reader won't communicate or it communicated and says no codes?

2) Can your scanner show pending codes or code history?

2) Have you tried to read the codes when the CEL is on?

3) Was any work done right before this started?

3) Can you look at live data with your scanner? If so you can check various sensor values to make sure that they make sense. If so equipped you can also look at misfire data, O2 sensor behavior, fuel trims, etc.

4) Have you tested your fuel pressure per the sticky?

I agree that throwing parts at the problem is not the place to start.

George