98 Blazer Trouble Code & Misfire

[Jay_1812]

Hi there,

I'm driving a '98 Blazer with a 4.3 at 172,000km (100,000ish miles) and occasionally I get random misfires when accellerating. Out of no where they will just disapear.

The diagnostic code came up with P0300 which is just a random misfire code. I pulled this code after I had washed the engine, the vehicle didn't want to start, when I did get it started it was a poor drive all the way home. I plugged the vehicle in, started it in the morning and it ran fine.

The last time I washed it was in October, I degreased the engine and rinsed it out and had no such trouble so it's something that has happened since then. I think I've put on 2,000km since, if not less.

I'm hesitant to use that error code to diagnose the problem because I did pull it off just after I washed it. The engine light has come on before but I didn't have the tools to pull the code. I thought maybe it was water in the gas tank but after running 4 tanks and a bunch of gasline antifreeze through it still hasn't fixed the problem.

The wires and distributer cap are new, top of the line, and were done at 156,000km last spring. I'm not sure what brand they were but the person who did the maintenance is a trusted associate and automotive tech.

There was also a small leak on the intake manifold. Should I get this fixed immediately if I'm not planning any long trips? Say, over 100 to 200 miles? Or can it wait until the weather is warmer?

Thanks for the help.

[Chris Stewart]

You might wipe off the sparkplug wires & boots one at a time...you might find some with some corrosion or cleaner grunge.
Wipe out the inside of the distributor cap, moisture corrodes the terminals inside.

The coolant leak at the intake manifold can get serious and overheat(destroy) the motor, it should be repaired in a timely manner.