97 4.0 ohv miss/stutter

[offrdron]

Ive got a 97 4.0 OHV 122000 miles and the engine seems to have a miss or a stutter. it happens throughout the rpm range but is very bad at 1500 rpms.its enough to shake the steering wheel.It happens in park or drive and has a considerable loss of power.Ive replaced the plugs, wires, fuel filter, cam position sensor, coil pack and have used sea foam.ive cleaned the maf sensor and checked voltage and resistance wherever i could. The truck also does not perform well on any thing other than premium gas.the codes have been scanned with no results and ive not gotten a check engine light. any suggestions would be great.

 

[TPLYNCH]

When you say you've seafoamed, are you talking about the carbon cleaning??

Have you checked all your vacuum lines for leaks? Make sure all the unused lines on the "octopus" are plugged?

 

[Diggman33]

if it aint motorcraft its a crap shoot

Seems silly, but I've heard from a few Ford service techs that the 4.0's are kinda peculiar when it comes to spark plugs. Seems that the Motorcraft platinums are the safest plug for the 4.0's although Im sure some will disagree. Have you ever had your PCM reprogrammed? Could be that or a vac leak or an O2 sensor - good luck let us know how you make out.