no problem. din't mean to hi-jack the thread.

 

Sorry Kyle

 

No, not a problem at all. No hijack either, but trying to help both of you in one thread was getting a bit confusing.

 

Have you thought that you may have a bad ecm? I work in an auto parts store and I have seen it more than once. Very rare but it does happen.

 

Hello new to site

Did you figure out problem

Blazeofglory (gator)

I read the entire post. Im shaking my head my 96 blazer is doing the same thing. I started with change fuel pump & filter to cap rotor wires plugs seafoam twice. Tired of spending money onno fix. Took it to a shopthe first time said it was coil and wires. I changed coil wires no fix I had a used coil off a sandrail build. Then the shop said it was fuel pressure regulator, they changed that still no fix. Took it back they said it was still the coil showed me on the side of coil white marks and stated high voltage. SoI changed to a new coil wires plugs. still misses not as bad. My wife is driving it so you know my pain!!!!!!!

I going to take it to the dealer to see if they can figure it out.

Could it be the ECM??

 

not sure if this is relevant or not or if it will help anyone as I have not confirmed it as of yet I just bought my 98 blazer it seems to have the same problem surges and sputters around 1500 to 2500 rpms under light acceleration but not under hard acceleration or at idle I have plans to fix it next weekend I have done a lot of research on this and one major one that I have not seen listed as of yet is a leaking intake manifold gasket. Like I said I have not confirmed this as of yet but more than one mechanic that I have talked to has told me this can cause the problem and is very often overlooked I will update once the repairs have been made to let you know if this fixes the problem.

 

A leaking intake manifold gasket should be found through all of the vacuum leak diagnosis already suggested here. If the intake manifold were leaking, it would result in a misfire. I would think it would result in a cylinder specific misfire (P030x where x is the misfiring cylinder).

For those going through this thread, I have created a P0300 Explained thread in the DIY section.

 

good point sorry I must have missed where he searched for the vacuum leak I'll make sure I read more thoroughly next time

 

I found this forum as I was having misfire problems with my 2001 Blazer, now at 146,000 miles. My wife was discussing thatI should be trading vehicles now so that we would avoid having two car payments at a later date, I was somewhat reluctantas the Blazer was really running pretty good. I had gotten a good deal on a set of E3 spark plugs and had installed them late summer, the vehicle didn't run any different except maybe a slightly rougher idle after the plug install. About a month later while helping my son out in the boonies I had a no-start, after the tow truck driver arrived we determined that I had no fuel pressure and likely a dead pump. The fuel pump was replaced and the Blazerwas running good again. A few weeks later the Blazer come down with all of the symtoms descibed by Blazeofglory. I did an ignition tuneup - wires, cap, rotor, coil- and poked out the little screens. It had been 45,000 miles since the last tuneup and there was some corrosion in the cap. No change, still rough running, still throwing P0300. I went to the local dealer for a check-up, they reported a P0306 and suggested treating with injector cleaner. The next few weeks were somewhat better with heavy doses of cleaner and worse without. As I was pretty sure of injector problems I installed the MFI spider injector conversion. While replacing the old spider I noticed that spider wasdamp with fuel and also damp at the number 6 intake port. The Blazer ran way better but still a little rough at 1500-2000 rpm and still throwing P0306 and P0300. Next was to change number 6 plug, wow - new vehicle again. Here's what I think was going on: The E3 plugs have a wider gap than the standard plugsforcing more voltage to jump the gap, apparenly I have something marginal in the ignition causing the misfires. Replacing the fuel pump possibly incresed fuel pressure making the spider weep near number 6. The fuel dripping down number six fouled the plug causing the P0300 and P306, replacing the plug clearedthe fouling and with a narrower plug gap was easier to light.The fuel injector cleaners have more volatility than gasoline, this would make the fuel easier to burn and have fewer misfires. If there was a leaking intake gasket this sould have been taken care of during the MFI spider installation. At any rate after twelve hundred in mostly parts the Blazer is running again.

 

Thank you for sharing your experience with the P030x code. I hope you ditched the E3 plugs. Or you will likely be having more problems in the not to distant future as those plugs are not long life plugs. AC Delco double platinum or the new AC Delco Iridium w/ platinum ground tip will last a VERY long time.

Also, just a friendly word of advice, please use a little formatting (#6) to break up your post to help people read it.