Misses under load

[moparcanuck]

It started running rough when it was cold then it smoothed out as it warmed up. Now it misses all the time but only under load. If I rev it up in neutral it runs great. Suggestions?

Stock 440
Automatic
Six Pack

 

[ga66mopar]

The last time I had an issue like yours my engine needed a new set of plugs.

 

[Hemi Rebel]

Thats sounds like a good ol' fashion American misfire. Sounds like you need a tune up. What ignition? Stock? Aftermarket? Points? Electronic?

 

[HT413]

I'm sorry, every time I read the title I see Mrs.

 

[moparcanuck]

Electronic ignition.

Ah yes, Mrs. Underload. I know her well. :toothy10:,

 

[AR67GTX]

If it misses under light load but will accelerate cleanly when opened up - I have found that to often be a bad set of plug wires. If it starts missing as you are accelerating into the upper rpm range, then I have found that to often be worn distributor bushings. If neither of these fit then it's probably the plugs or distributor cap/rotor. I guess the electronic iginition module is another possibility.

 

[Joeyt66]

Usually plug wires when this happens. But check the plug condition too.

Good Luck!