4.0 engine misfire @ low rpm under load

[dford]

Just changed my fuel filter, plugs (autolite double platinum) and wires ($80.00 + from car quest) When cruising along in 5th gear at slower speeds and then stepping on the throttle, I now have a momentary stumble before it smooths out as I accelerate. Coil pack is original--98,000 on the clock. Clean air filter. Any ideas what to try next. Aside from low mpg, it ran great before this "tune up". No misfire codes indicated from OBD.

 

[E.B. Cornburner]

Could be a coil starting to go. That'd be my first idea. Either that, or an injector that's getting a little tired.

It's even possible that you got a dud spark plug. I've seen it happen if one gets dropped in shipping etc. If you can isolate which cylinder is missing, try changing that plug out and see what happens.

 

[dford]

I'll give the coil pack a try...any brands to stay away from?

 

[dford]

I'll give the coil pack a try this weekend. Any brand names to stay away from?

 

[E.B. Cornburner]

Stay away from Wells, and GP Sorensen. AutoZone sells Wells, and Advance sells GP Sorensen.

NAPA's Echlin brand is good, Carquest carries Standard, which is good, and Borg-Warner parts, available at many places, are good.

 

[dford]

EB Cornburner, Thanks for the info. OBD finally threw a code...turned out to be a cracked sparkplug. Running smooth again.

 

[E.B. Cornburner]

EB Cornburner, Thanks for the info. OBD finally threw a code...turned out to be a cracked sparkplug. Running smooth again.

Glad you got it figured out. Sometimes it's the simple things that are the most easily overlooked.