I have a 2000 Chevy Blazer,2 Wd, 4.3l v6 120,000 miles.I bought used for $3000 with 92,000 miles in January 2008...runs well with few exceptions. I have a slight buck when it goes from 1st to 2nd gear, but thats nothing im too concerned about .Every so often "service engine soon" light will come on. My code reader gives me P0440 code ( Evaporative Emissions System ). Going onto the OBD 2 website I read that this shouldn't give me any severe driveability issues so I've sorta been lagging on it, also I don't really have the technical know how on how to fix or, nor can i afford to take to a repair shop at the moment, so I've sorta ignored it for a while. ehh.... Another problem I have is sometimes when I'm driving on the freeway the light will come on flashing. When i read it this time it gives me the P0304 code ( Cylinder 4 Misfire ) or just a P0300 ( Random/Multiple Cylinder Misfire ) which will eventually reset itself. It usually happens when im at speeds around 65-75 mph, mostly when im accelerating at higher rpms. Also my vehicle hesitates going up longer inclines on the freeway, having trouble sometimes getting past 55-60mph going uphill. Also sometimes if I work her too hard up a hill the light will come on flashing and it will give me a P0304 or P0300 code. I've replaced the spark plugs, wire sets, caps, and rotor but the misfire still occurs occasionally. With the exception of these hiccups the vehicle has treated me very well and hasn't failed me yet. The biggest problem I had was a major hiccup while taking a 100 mile drive to San Diego from Los Angeles. I was driving on the freeway with the cruise control on at about 65-70mph, when i came to a hill..the cruise control jumped my rpms from about 2,500 to 4,000 to maintain the speed i was going. When this happened the "service engine soon" light came on, my vehicle started to slow down, and a foul smell started coming from my ac vents. I got up the hill to flat and I pulled over and turned off my vehicle. My code reader gave me P0300 ( Random/ Multiple Cylinder Misfire). I let my vehicle sit for about 10 minutes, then i started her back up and continued my drive without any real problem, ( at this time only about 25 miles from my destination)...the light reset itself before I reached my destination. My vehicle performed well for the 7 days in san diego. for the 100 mile drive back, i took it easy , not passing 2,500 rpms on the freeway and going slow up hills.I made it home without a problem. when I got home I replaced my plugs, wires, caps, and rotor. discovered the wire on the 4th cylinder was pretty damaged.I felt an improvement but still have hesitation up hills and P0304 code comes up occasionally and resets itself. Anyway thats my story and problems I have. If anyone can help me out with whatever knowledge I would appreciate it. Thanks for taking the time to read....

 

hello i'm new here to. i had the same problem with the P0300 ( Random/ Multiple Cylinder Misfire. and sometime it would say misfire in cylinders 2and 4.. i did the same thing you did, when i got my 98 blazer i change replaced the spark plugs, wire sets, caps, and rotor. then about 11 month later it started with the code's and misfire. i had no ideal what was going on with my blazer.... so went back to advance auto parts and got ACDelco Spark Plug(Part No. 41-993 ) PLATINUM PLUG; @ GAP .060 @ they cost me 6.59. each plus taxs.and re-repalce the cap. afters this the misfire wheer gone ...but .......but.... 10 month later thet misfires started same code. i still ahd warranty on the cap went back to exchage got back home put it on and no more misfires. if this dosn't work then you might have to change the Distributor ($95.99 ) well i hope this was helpful and good luck