I have a 1998 Explorer 4.0.

Truck runs great, no misfires or hiccups in motor.

When in drive at any speeds even highway, the motor is not going over 3000 rpms.

New plugs and wires recently, MAF sensor cleaned.

Any idea what else would cause this?

 

Will it rev over 3k in neutral? Could be among other things, clogged catalytic converter, TPS (throttle position sensor),maybe low fuel pressure although other things may come into play.

 

Welcome to the forum!

Have you checked for current and pending diagnostic codes?

-Rod

 

Thanks guys.

It revs fine when in neutral, I checked the other day.
I have had it on the computer at a friends shop and all cylinders were firing fine. At first I thought it was ignition related.

I am pretty handy so I'd rather try to figure it out before taking it to a shop or dealer.

 

Remove a pre-CAT O2 sensor, (It will be noisy), if runs OK, partial clogged CAT.

 

Problem fixed and by a fluke!
Went to mechanic and booked future appointment... a few minutes driving away my gas pedal bracket falls off!! No one I have talked to has seen that happen before...
So needless to say that I drove about 8km back to mechanic by holding pedal in hand and pulling throttle cable!! But diagnosed my issue... it was just the bracket losening and just needed more gas... I fell like a retard cause it has bugged me for awhile and I couldn't figure it out, nevermind the amaount of gas I used driving under less power... and towing my work trailer often.
So, got a screw throw bracket and a weld and back in business... a quick fix to something I thought I was gonna spend huge on....
Just think if I took it to a dealer, they would have raped my wallet and still most likely might not located the issue.

 

That's twice I've read on a forum about a accelerator pedal coming loose from the firewall. I wonder if this is the start of a new trend/common issue.

Thank you for posting your finding and fix!

-Rod