Engine shaking at idle

[Hitchhikingmike]

I just took mine into the shop for this same problem. It has been doing this for about 2 years now, gas mileage 18mpg highway, i have changed the plugs wires fuel filter, cleaned the TB, nothing seemed to help. Well they smoked tested it and here to find out the intake manifold gasket and the O rings on all injectors are bad. haven't fixed it yet, just put $300 into a wheel bearing so the other stuff has to wait.

What engine do you have and what year? just wondering.

 

[dvalot03]

04 with 4.0 78k miles

 

[dvalot03]

Just as an update....replaced the fuel injector o-rings and intake gaskets and the problem is still there and is actually worse I am totally confused on what it could be. Its going to the shop next week. Anybody have any ideas? No check engine light, but it does have a miss sound @ the exhaust (new plugs and wires). Does the '04 have an IAC, the kid @ the parts store tried to sell me one but i was unsure if it had one since some on here say it doesn't

 

[2007joker]

Mine does the same thing on and off its not constant at all. But I noticed my rpms fall below 500 when it starts to shake.

 

[tonydp]

sounds like 2 different problems? mine has an engine shake but rpms never drop or flucuate, they hold steady. Just feels like a gentle massage. maybe a motor mount?

 

[Sick04EBEdt]

My whole vehicle shakes too, only at 900 RPM though. I am soo confused, it just started doing it all of a sudden. Once i accelerate it seems normal, then i come to a stop, the idle drops to 900 RPM then it starts up again, only does it below 1000 RPM's...

Not sure what it is, vehicle is 2004 Explorer 4.0 V6... i wrote down a bunch of stuff to try from this post. If anyone has any other idea's or the same exact problem that they got fixed please let me know by post or PM. Thank you.

In the mean time i will try to tune up, vaccum lines, ohh also i havent gotten any codes or CEL's so thats what is even more confusing... help!

 

[4dlover]

chain tensioner

My guess would be the balance shaft chain tensioner has broken the only reason ford put the balance shaft on these engines was for a smooth idle, many dohc neon owners actually remove the shaft to save weight but the only real adverse effect is the idle vibration, i have been trying to figure this one out for a while now and i m sure that has to b it if there was a vacuum leak the pcm would show a code of some sort as manifold vacuum would be lost and the sytem would try to compensate for it with more fuel and a higher idle! as for the rest of the possibilities they are all plausable but this is the only thing other than the balancer that could cause a vibration! So as u can c this has to b it! If the dampner was bad it would shake at every rpm!
if you have a question please feel free to write me and look on some of the timing chain threads and u can c the tensioner and how difficult it is to get to! thanks chris

 

[Ford Vehicles]

Blocked catalitic converter

Just as an update....replaced the fuel injector o-rings and intake gaskets and the problem is still there and is actually worse I am totally confused on what it could be. Its going to the shop next week. Anybody have any ideas? No check engine light, but it does have a miss sound @ the exhaust (new plugs and wires). Does the '04 have an IAC, the kid @ the parts store tried to sell me one but i was unsure if it had one since some on here say it doesn't

Did you ever find out what was wrong with your Explorer? Just for future reference, Check temperature on both catalytic converters. Mine is not throwing a code either but one converter is 400 degrees and the other is 900 degrees. Which means one is blocked!!