92 XPLR severe vibration during acceleration

[FenderStratMan]

1992 Explorer 4.0L w/Auto OD 2WD

A fairly significant vibration while accelerating (side mirrors vibrate badly).

Vibration quits once you let off gas.

U-joints and drive shaft bolts look okay. Trans fluid okay.

No slippage from a standstill. Shifts to all gears.
Tires and wheels okay.

Engine smooth w/no miss while in park or neutral.

Tach bounces around about 500 RPM when vibrating.

Loss of power but I can't tell if it is trans slip, or spark advance, due to the vibration.

No vacuum leaks. New plugs/wires. All connectors/wire seem okay.

Code scanner said throttle position sensor but replacement didn't help. Still get code.

Any ideas?

thx in advance

 

[MrShorty]

What TPS code? Is it KOEO, KOER, or CM?

Spark advance is almost never a problem on these, but it can be checked if you want to know for certain. See ignition timing tests at www.dalidesign.com/hbook/eectest.html

Motor mounts and transmission mounts look ok?

 

[FenderStratMan]

I am thankful for the reply MrShorty.

The last time I REALLY worked on my own vehicles they didn't have computers in `em. I found from the sight you sent that I really just wasted money on the code scanner I just bought, could've just used my meter.

I guess the intimidation factor overwhelmed my common sense. I gave the MOUNTS a perusal didn't really check them out thoroughly. I will get a jack under there right now.

Would it be common in the case of mounts to have 500RPM swing during acceleration? It is swing where the tach is bouncing back and forth pretty rapidly ~500rpm delta.

If the mounts are okay, do you have any ideas what other possibilities are likely?

 

[Glacier991]

It is also possible to have driveline U joints move farther out of balance on acceleration giving vibration that seems to go away once everything is moving more in synch....