5.0 Explorer Motor in Fox... Has vibes above 3000

[jaketuff]

Bought a nice looking Fox that has a the 5.0 Explorer Motor/ Upper End anyway.

I notice a vibration that seems to be motor not tranny above 3ooo RPM. The motor seems to feel like it is losing power as the RPMs increase. Feels like the motor is "slipping" rather than the clutch or tranny.

She sounds very lopey and healthy at idle. It has the stock cam, stock 'Explorer' motor, p/o clutch. Combo has less than 20k miles. Car doesn't pounce off the line like it really should. No apparent computer issues. And spark seems fine.

Feel bet action is to:
Test Compression
Dyno power to the ground (have access to dyno 4 life at a shop)
Change Fuel filter, tune up just in case its something small

Ideers?

 

[Gearbanger 101]

The stock Explorer motor signs off not long after 4,500RPM. The stock cam was ground more for low end torque, rather than performance. Most owners swap out the stock Explorer cam for the HO cam out of the Mustang engine along with a set of stiffer valve springs to keep floating the valves under control.

Your above suggestions are all good steps in the right direction. Couldn't hurt to check your ignition timing too.

 

[hoopty5.0]

uhhmmm..... Stock cams don't lope. Ever. So you may want to look into other areas too, like plugs, wires, cap, so on...

 

[stykthyn]

Ditto. Stock parts should be smooth like a sewing machine.

 

[jaketuff]

Maybe I mean moreso lopey than other rides recently... Just got this 5oh and miss the old sound of the motor... To be correct motor is smooth and glubs like a regular 5 liter. just plain gets odd higher in the rpms...

Could it be the explorer motor plain topping out in output at 4000?

 

[stykthyn]

Doubt it. I would go through the surging idle check list at the top of the tech forum.