P0300 Flashing CEL '01 Blazer LS
 

Hello. My mother gave me her '01 blazer, she bought it new. The problem am having is a flashing CEL that comes on and off. Then it goes off or comes on completely. First things I fixed in this order:
Smog pump system...blew up.
One-way check valve from passenger side manifold.
Cut off clog CAT...put str8 (flex) pipe. (Temporary)
Distributor cap & rotor.
Spark Plugs (gap=60) and cables.
Clean air mass senor....still flashing.

The truck drives great after removing cat. The truck has 112k and always been parked in garage. Only code i get from the cpu is P0300 random misfire generic. Today, Im going to get some carb cleaner and check for leaks. Any help will be appreciated.

Work through this post P030x Explained (x=0,1,2,3,4,5,6) plus the link at the end of it.

Thanks Rriddle3.... will do. Performed the carb cleaner test for leaks and none found to the naked eye. Next up will be to replace my ignition coil.

Check your fuel filter, and your fuel pressure at the spiders. After months of diagnosing my P0300 code, and finding out last week that my truck doesn't have a EGR (late 2002), my friend tested my injectors...weak, but traced it back to my extremely clogged fuel filter :icon_doh:

Thanks Mykeboy01, I will try to get someone to check the fuel pressure on my spider. The thing was that I know for a fact that the fuel pump and filter were replace more or less than a year ago. But again, that clog cat could have cause mayhem.

So, now waiting for my blazer to cool down...so in the mean time I was wondering if anyone had words of advice on how to install the ignition coil. Its in the original equipment mount. Instructions in the new coil states that I might have to destroy my original mount to install replacement coil....models affected: 50007, 2-50007 Coil.... does this apply to me and if so whats the work around to install new coil? Thanks in advance.

You have to remove the bracket from your block, *requiring removal of the throttle wire thingy bolted to the top of the bracket*, and chizzle out the two rivots *preferably on the driver side of the coil*. Your replacement, if it came from the dealer, will come with bolts and nuts to replace the rivots. It took no time at all, really. Good luck!

Thanks Mykeboy01. I removed the brackets and end up using a chisel and hammer and those little rivets came out flying off that mount like butter. No luck though. Going to check fuel and vac pressures today....also looking for a diagram of all engine grounds in my vehicle to check if ungrounded wire is causing misfire. Thanks for the advice.

i have a 2002 blazer and my CEL came on about 2 weeks ago after i had some rough idling. It ended up being the p0300 random multiple cylinder misfire. luckily for me all it took to turn it off was to give it a good flooring of the accelerator. I assume it was just a bad batch of gas. it hasnt come back on yet and its been almost a month. im gonna start replacing spark plugs, ignition coils, wiring, and the fuel filter just because its about that time anyways. try getting on the highway and revving it to about 4 rpm and go through a couple gears. because spark plugs are a bitch to replace on these cars

Hey there. To just to keep everyone updated.....here are the things I have done thus far to try to solve flashing CEL and misfire(po300) on cylinder 1 and 4. (NO MISS FELT/NOTICED)
*MFI Upgrage includes fuel regulator
*Clean EGR +new screened gasket
*Clean crank sensor / new cam sensor (edited)
*Checked all grounds front to back.
*New LIM gasket (cleaned prior)
*New Heads
*New radiator
*New temperature senor.

and guess what.... same thing still reading. I know that the head had to be warped since all that heat from the clog cat.... took both heads to shop and were no good. This is not about how much I've spent on this truck its about problem solving this issue because I LOVE my truck! =)

I get fouled stark plugs on 1 and 4........so i guess i should now replace the o2 sensors or do I have stubborn historic code? Any thoughts?
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