1996 Chevy Blazer Misfires when cold

JARCHER

MEMBER
1996 CHEVROLET BLAZER
6 CYL
2WD
AUTOMATIC
180,000 MILES

When my blazer is cold (not up to 195 degree operating temp) it will misfire when I am accelerating. It does it the worst at about 2500 rpm just before it shifts, but I have to let off the gas pedal in order for it to shift. If I keep my foot on the gas while it is misfiring, it will just keep jumping around and the rpms fluctuate up and down. While I am on the highway in overdrive, it seems like the blazer is surging and I can see the rpms jumping back and forth from 2000 to 2500. Under hard acceleration, the blazer also surges in the same way as at highway speeds, but will shift fine. After I drive about fifteen minutes, all the misfiring stops. What could this be?

3 Replies

GREGVOGT

MEMBER
3 POSTS

You've got alot of miles there.
Shifting Issue.
1st check transmission fluid for coolant, also check radiator for any oil or transfluid floating.

On missfire, do you have injector or spider injector?
Is it hard to start or taking long to fire off?

The Firestone guy

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Monday, January 12th, 2009 AT 5:44 PM

JARCHER

MEMBER
3 POSTS

It has the spider injection. It starts right up without any problems. The trans fluid looks and smells fine. I have bought a new truck but still have the piece of crap blazer so I would still like to know how to fix this problem. Coolant looks just like coolant should. While this problem is occuring the SES light will repeatedly flash (indicating a misfire?).

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Monday, January 12th, 2009 AT 7:48 PM

GREGVOGT

MEMBER
3 POSTS

We just had a blazer in the shop with the same problems, I will pull the history on it and post the fixes we did to stop it.
I know she had a coolant sensor that was not sending the right values, her distributor and rotor were corroded. The fuel pressure regulator on the spider was leaking by but that was a flooding problem, but it did foul the plugs.
If you access to a scan tool see which cylinders are miss firing and pull the plugs and see if there loaded with fuel.

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Saturday, January 17th, 2009 AT 11:12 AM