razgs300

Hi guys, my GS300 is in the garage now because it developed a misfire. It started fine but when the engine had been warmed up and running a few miles, it misfire. The engine sounds like its going to die and its shaking. My mechanic had changed the spark plugs, checked the coil packs but it still misfire. What causes it to happen and how it can be fix?

StealthGS

iTrader: (2)

This just happened to me on my 98' GS300. And it was jumping spark, The problem was the wires. One of the boots got torn, And was causing the misfire *Only when warm*.

I would inspect the wires, Or just replaced them!

razgs300

When u mentioned wires, you are referring to the spark plug cables right?

daxnizmo

I'm sure he is. Start pulling one and listen to see if the idle/rpms drop and then go to the next one. If you hear no change, then that plug and wire has an issues. If you unplug the wire (cable as you said) and the rpms drop, then that cylinder is fine. I'd go ahead and replace all the wires if can. How many miles are on the current set?

Dueces

iTrader: (3)

is your check engine light on as a result of the misfire?

razgs300

I believe the current set are still the original cables from new. The car had 120k miles on it now

Nope, no CEL.

daxnizmo

I'd say go ahead and get new plugs and wires then. That would be MY first move. Good luck.

Dueces

iTrader: (3)

he changed the plugs already

daxnizmo

I FAIL at reading, lol. Well have the injectors been checked?

Dueces

iTrader: (3)

no worries man it happens. thats a good question tho.

razgs300 have you tried some fuel injector cleaner or something?

StealthGS

iTrader: (2)

I would agree on the injector/fuel cleaner. I personally Sea-Foam all of my vehicles when I first get them!

Follow the basics = Oil change. New PCV Valve. Clean MAF. Spark plug change ONLY USE = (Denso Iridium/Platinum, Or NGK Iridium/Platinum).

The mis-fire with no CEL can usually point to a fuel problem, And again not always. I had a lean code for a while, And we replaced the MAF and it fixed that problem. But the mis-fire kept spitting out P0300 And P0303. It ended up being a bad Spark Plug Wire!!

My 98' Has 130k. So I would grab a set of wires and you should be on your way!!

Dueces

iTrader: (3)

Good to know am gonna try some of that. How does this Sea-Foam procedure go? PM me if you don't wanna inturrupt the thread.

razgs300

Nope, the injectors never been checked. I will tell them to have a look at the injectors.
I never use any injectors cleaner on my car though. I will after this hehe

Now, I gotta have a thorough look at the wires to see if they are the main cause of the problem.

I would like to know the procedures too mate

Dueces

iTrader: (3)

looks like its gonna be a thread post

razgs300

I was told that the oil timing control valve was faulty and causes the engine sputtering after the engine had warmed up and been driven a few miles. Is that true?