misfire problem

[Sergeia]

Hi everyone .My 98 jimmy started to have problems.Then it is at idle it start to vibrate like if sparkplug misfire.If I acclerate it will be gone for a while .Sometimes it does it ,sometimes not.I waited oter day till check engine light ,.Scaned for code it say p0300"random/multiple cylinder misfire detected" .I gess I have to mention new spurkplugs and spurk wires was installed.If anybody could help or have any idea whats wrong with it ?Thanks a lot

[maxwedge]

Check for spark to each plug with a cheap spark tester, if all are ok, check for a cracked cap, if ok, recheck plugs for a misgapped or cracked plug, BTW, did this happen before or after the plugs and wires. Of course you are sure the wires are on the right plugs!

[Sergeia]

Yes.I changed plugs and wires after it is started to do this.This is why I changed it .I had this truck for 5 years now and 110 k on it ,never had problems before.One of my buddes suggested to change computer .Don't know what to do?

[jimmyMonroe]

I own a 96 and was getting P0300. I found a small hole (or melted area between the #1 and #2 runs on the underside of the distributor cap. It looked like there was a crossover in the spark between the two causing a misfire. I changed the cap and it fixed the problem. Another indication was a fouled #1 spark plug that had recently been changed.

Also search this site and the blazer site for P0300 code.