4.0 a little shaky

[AKBroncoII]

I have a 91 explorer and for some reason when it idles down, around 800RPM, it shakes a decent amount. More annoying than anything. Does it whether warm or cold. It has a slight shake throughout RPM's although more so at idle. I replaced the spark plugs already so I know they are good. Any help would be much appreciated.

 

[Beanmachine7000]

Yeah, I have the same problem except mine is between 1500-2000RPM... It's more annoying than anything...

 

[AKBroncoII]

Yes, very annoying. I figured I would be getting a code for something but nada. I am wondering if my fuel filter isn't clogged. My truck seams to run a bit rich and high on CO levels.

 

[AKBroncoII]

No one? What are tell tale signs of a bad fuel filter? I doubt it has ever been changed in 128K miles.

 

[AKBroncoII]

okay, it's some sort of miss but I can't figure it out. New plugs no wires though. Replaced MAF, TPS, and IAC. Still a miss that is worse at idle. Time for new wires? Gets worse at low RPM.

 

[joe22]

I would definitely change the fuel filter. I had a stutter problem at low idle and a new fuel filter corrected the problem. I'm sure my filter had over 100K miles...the vehicle has 174K now. Also, a new fuel filter will improve starting and allow the fuel pump to run with less effort.

 

[Rico]

Changed the motor mount and problem solved. My camaro had the same problem. I kind of noticed it while driving but really noticed it shaking will at a red light. I took out the bad mount and could really see why it shook so much. Hope this helps.

 

[AKBroncoII]

I am fairly certain it's not a fuel filter problem. No bad motor mounts, it's definitely a miss. Changed plug wires, still happening. stuck valve? I will probably just pick up a fuel filter anyways as I'm sure it's never been changed.

 

[cr_the_machinist]

I am fairly certain it's not a fuel filter problem. No bad motor mounts, it's definitely a miss. Changed plug wires, still happening. stuck valve? I will probably just pick up a fuel filter anyways as I'm sure it's never been changed.

My '99 4.0 Ranger did the same thing. I change the fuel filter and no more! I have never changed it since I have owned it (since 69,000 miles). I changed it at 88k and it puked out a bunch of crud out of the unfiltered side and I could barely blow though the filter. Check it out.... its only an $11 part!

 

[sward1979]

Does it use any antifreeze. Have you done a compression check.

 

[The Fox]

Could be something as simple as a vacuum leak. If it goes away at higher RPM(less manifold vacuum), it is most likely a leak.
Nick

 

[AKBroncoII]

wouldn't a vacuum leak cause it to idle higher? IE, air getting into the intake causing RPM's to rise? That doesn't happen. The only antifreeze I lose is onto my floor. Fuel filter getting changed right now. Then I'm going to swap in another coil I have. I suppose it could be an injectory issue also. Oh yeah, it doesn't go away with higher rpm, just not as noticeable.

 

[AKBroncoII]

Swapped in new coil. Still slight miss. I did find out that the shaking of the engine was the clutch fan. Luckily I had one that was fairly new laying around. I may just have to live with the slight miss. I can stick my hand on the engine and feel it missing now and again. Thinking it might be time for new injectors or to get these cleaned.