Have 2002 with the 5.4. Has 142,000 miles. Plugs changed about 2000 miles ago.

It just started surging. Going down the road and tach would rev and the speed would stop for a second. Then was in a parking lot idling up the lane looking for a spot and it actually speed up like the transmission shifted.

Then it has stalled a few times, once after just putting it in reverse and once stopping at a stop light.

Is this a coil issue (they haven't been changed)? And no check engine light has surfaced.

Thanks,

Gregg

 

Might be coils by the sounds. Mine recently started bucking like it wasn't firing on all 8, turns out it wasn't. Idle was fine mostly but get it a bit warmed up, it did not want to run. This problem often gives no codes, but you have gotten a good life from your coils so might be time for new ones.

 

The only way an engine will increase in rpm is with more air same as applying the thottle or the IAC opens farther..
You have an air intake leak at some point.

 

Could be a mass air flow sensor... Mine did some strange things like yours, changed the sensor with a used one and haven't had the problem since

 

Bigredpei,


Did it throw any codes? What led you to changing it?

Thanks,

Gregg