96 3.1 lumina miss fire under acceleration

[lynnesbrett]

i have a 96 lumina with 3.1 v6. There are no codes as of now. It idles fine, starts great and runs great until i reach about 45 mph. Then it miss fires and chugs and hesitates under load. It will do it from 40 to 70 mph never around 25 or 35 mph tho. I dont know where what to do it is starting to get worse.

[Tech II]

How many miles on vehicle? Last tuneup?

With car at normal operating temp, apply brake, apply e-brake, step on the gas and raise the rpms, does it misfire?

First thing I would do, is pull the wires off the coil terminals one at a time.....if the terminal is ok, put wire back on and check the next one......if you find a terminal corroded, that is your problem.....can try sanding the terminal, and cleaning the contact inside the boot of the wire...apply dielectric grease...install wire(might have to crimp the contact inside the boot if the wire is loose on the terminal).....

If that doesn't take care of it, you will need to remove the boot off a spark plug, one at a time and attach a spark tester, to check coil output......do all six.....if you have poor output from the terminal you cleaned, you will have to replace that coil and all the wires.....if the plugs have not been replaced in a long time, now would be the time to do it......make sure you use A-C/Delco's.

[lynnesbrett]

It has 147,000. I have had it since 110,000 and have just done normal oil changes and little stuff here and there i have ran lucas injector cleaner threw it every oil change. Havent touch plugs or wires yet. The contacts on wires and plugs were not bad but a few were iffy. I didnt know if that would make it miss fire the way it does but i will replace the plugs and wires.....also my cruise control stopped working about 500 miles ago. Checked connections up to the module and all was ok. Any suggestions? thanks

[Tech II]

Sorry,

With car at normal operating temp, apply brake, apply e-brake, step on the gas and raise the rpms, does it misfire?

Forgot to tell you to put it in Drive.......

If you replace plugs and wires, remember to use OEM plugs.....and make sure coil terminals are clean....apply dielectric grease to the coil terminals and the plug terminals......

If it still misfires, need to do a coil output check with a spark tester.....