Misfiring at IDLE - Code says misfire - runs good & 3000rpm

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Misfiring at IDLE - Code says misfire - runs good & 3000rpm

Postby OrlandoSonomazr5 » Fri Jul 03, 2015 11:27 pm

So my truck today started misfiring and thru a code, I've recently replaced the distributor about a month ago, new plugs about 6 months ago and new wires as of today.

Still misfires and barely runs or wont run at idle - but rev it up past 3000 rpm everything smooths out.

I'm thinking Ignition Coil.......

any suggestions or anyone have a similar issue.

And yes the A/C works and is full.
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Re: Misfiring at IDLE - Code says misfire - runs good & 3000

Postby HenryJ » Sat Jul 04, 2015 6:07 am

Check the cap and rotor. It could be loose or bad.

New parts don't always mean good parts. They are used as soon as you install them. New parts have failures too.

The ignition coil is usually good or dead, while a misfire is possible and there can be some pretty severe leakage, a bad misfire at idle is not usually related.

Using insulated pliers remove each plug wire and see if you find one that doesn't change the miss. That would be the plug or wire to suspect. swap the wire and see if the problem moves. If it doesn't, pull the plug and check it. If it looks ok, swap it and see if the problem moves.

Check for vacuum leaks. Spray some carb cleaner around the suspect areas on the intake. Look for a loose or stray vacuum line.

Check the fuel pressure. Run the fuel system checks to rule out injectors, check valve, regulator and pump.
When was the last new fuel filter installed?
Have you been using some injector cleaner routinely?
Did you get some bad fuel?

Narrow down the suspects and then start interrogation ;)

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Re: Misfiring at IDLE - Code says misfire - runs good & 3000

Postby LoneWolf04 » Sun Jul 05, 2015 4:49 pm

Not sure if you are the original owner but the original fuel injector is known to clog and cause misfires at idle. The poppet valves stick from getting gummed up or debris a fuel filter did not catch. Like HenryJ said. Check all the routine things, make sure the "easy" things are covered before you start digging.
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Re: Misfiring at IDLE - Code says misfire - runs good & 3000

Postby Built2Bend » Tue Jul 07, 2015 9:51 am

I've on and off had a similar problem HenryJ pretty much covered every thing that I would suspect.
But my question is when my truck dose it it's on start up it will idle low and misfire with no code. But one I give it a some throttle 2,000 rpm or so it goes away and then the truck will run and idle just fine. Dose your completely go away or just temporarily go away
1995 s10 reg cab short bed 4 cyl stick (sold)
1998 s10 reg cab short bed 4 cyl auto
2004 Sonoma crew cab v6 auto
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