Explorer shudders at high speeds

[crossman]

I have a '91 Ex. Sport with the 4.0L and the 5-speed. Lately I have noticed that when I'm cruising on the highway above 60 mph and I start to go up an incline, the Ex. will start to shudder and shake. It almost feels like something is missing in the engine. At that speed, I have the tranny in fifth/OD and the RPM's are up around 2200. This will do it in other gears too, but only in the 2000 - 2500 RPM range. I have run a bottle of fuel injector cleaner through with no help and have also replaced the gas filter. Does anyone have any idea of what would be causing this? It is really starting to bug me since I can't really step on the throttle on the highway because the Ex. start shaking and shuddering so bad that it feels like it is out of gas. Note: This problem seems to go away if I get the RPMs up past 2600. Any help will be greatly appreciated.

 

[TPLYNCH]

Could be the MAS. Try cleaning it and see if it makes any difference.

 

[Paul Gagnon]

Sounds like you are having clutch problems.

 

[mmsdrummer]

I have about the same problem but I have an auto trans. I usually just let off the gas a bit so it will shift down until I get off the incline.

 

[crossman]

I'm going to try to clean the MAS and see if that helps. It helped a bit when I cleaned out the throttle body. There was a lot of crud in there and my Ex. ran better and didn't shudder as much afterwards. Today when I took it for a ride, I noticed that it won't do it unless I'm under power in 4th or 5th gear and going up an incline, so hopefully cleaning the MAS will fix it.

By MAS, do you mean Mass Air Flow (MAF) sensor?

 

[TPLYNCH]

Yes, MAS = MAF in my terminolgy

 

[crossman]

Thanks, I'll have a look at it and let everyone know how it goes.

 

[Sky1785]

My '91 Navajo w/ Auto Trans does the exact same thing, and it does it back near the rear axle and was told it could possibly be the universal joint, but if anyone does find a fix, please post, I'd appreciate it.