On all obd2 vehicles 1996+ a flashing check engine light means the the engine is miss firing so bad that raw fuel is being pushed into the exhaust system and is being blown right into your 600+ deg. f. catyletic converter which can destroy your cats and possibly cause a fire by over heating it and possibly melting it (worst case.)

I didn't read he was having any of those issues....he's been driving it.

Thanks guys! I checked my fuse box under the hood and inspected the cig lighter fuse. It was not blown and the outlet still has power to it. The second time the check engine light started flashing two days ago, the engine made brief exhaust rattle sound and i had the hood open at the time and could see the engine looked like it almost rattled too. Thankfully i did not continue to drive it after that happened.

As of today, the check engine has not flashed and there has not been any abnormal noises from the cab or the exhaust. Ill make sure to pull over if the light starts flashing while Im driving. I have a feeling that i have not seen the last of this issue, so i might break down and take it to the dealer and have them run the diagnostic scan for $116... :icon_shrug:

I was just trying to help him out. Im sorry if I have offened you.

Didn't offend me at all. Just getting clarification as I have never heard that before. Cheers. :icon_toast:

Ok good. glad to here it.:icon_toast: Ya not a lot of people know about that unless they've worked in the trade.

There are a number of things that can cause the engine to heavily misfire, but I wouldn't consider a blown fuse for the PCM - If a fuse was blown for the PCM and it had no power, you wouldn't be able to start the engine.

The definition given by carlb87 is correct (easy to find on an internet search), the cat's igniting is only a possibility due to temperatures and raw gasoline involved, but not a certainty - it probably wouldn't burn, but explode from the fumes igniting inside the cat.

Interestingly enough I had this happen when I installed the SVT injectors. The CEL light flashed and beeped and shortly after I got 'bank 1 & 2 running rich' codes (and I was). Happened every time I cleared the codes. Once the OEM injectors were reinstalled (till I can get a tune) the CEL did nothing outta the ordinary.

So my 2 cents is you have a internal fuel leak, possibly a injector sticking that is making you run rich intermittently, but maybe not rich enough to set a code, if that is possible. Try some injector cleaner in you fuel for a cheap starting point.
As for the not being able to comm with the PCM I also suggest trying another reader before you start worrying to much about that, maybe the one they tried was not CAN compatible.

i work in the trade. and i have never heard of that. also i asked my shop foreman who has been in the trade for 20+ years and hes never heard of this. care to share where you got said info from?

I first heard the explanation several years ago from dealerships of a couple of different manufacturers and then I looked it up on the internet where there was a lot more info on the topic. Dealerships can be useful :icon_biggrin: