Ticking when idleing and driving

[YountExplr]

I have a loud ticking during idle and driving. I replaced the egr valve and cleaned the IAC a bit and nothing changed. My dad thinks its something with the timing and I hope that he is wrong. Pretty much I used to have an intermittent rough idle and during good idle, if you pulled the hose off of the top of the egr valve, the rough idle would return. Now the idle is rough all the time and it sounds like it is coming from around the upper plenum.

Here is a video to hear the ticking. Dont mind the moving of the camera, I wanted to make sure I got a good quality sound.

 

[BestUsernameEver]

Ticking

Does the sound speed up proportionally to the rpm?

If it's just the idle thats rough... have you checked/cleaned your IAC valve on top of the upper manifold?

http://www.explorer4x4.com/iac.htm

 

[2000StreetRod]

Try to localize

A length of flexible hose held to your ear may help you to localize the source of the sound.

Is it louder for a few seconds when the engine is cold started?

If the source seems to be at the upper right rear of the engine, the upper left front of the engine or the lower center front then it could be a loose timing chain. To me the sound has a higher frequency than if it were a stuck lash adjuster or noisy rocker arm.

 

[YountExplr]

we systematically pulled the spark plug wires and found that only the plugs on the left hand side of the engine affected the idle, so the idle didnt change when we pulled each of the right hand side wires. 4,5, and 6 I believe because i was getting misfires on them this morning. So now im thinking this is a spark problem. So i pulled the plugs on that side and all of them have gaps in the .040 range. Can badly gaped plugs or old wires cause an idle like that? Or for that matter is there anything else that would make that whole side go bad?

 

[2000StreetRod]

Check the compression

we systematically pulled the spark plug wires and found that only the plugs on the left hand side of the engine affected the idle, so the idle didnt change when we pulled each of the right hand side wires. 4,5, and 6 I believe because i was getting misfires on them this morning. So now im thinking this is a spark problem. So i pulled the plugs on that side and all of them have gaps in the .040 range. Can badly gaped plugs or old wires cause an idle like that? Or for that matter is there anything else that would make that whole side go bad?

Low power can be due to spark, fuel or low compression. A bad coil would affect two cylinders (1&5, 6&2 or 4&3). The right fuel rail could be blocked preventing fuel to the right injectors but that should trigger a CEL with a lean DTC. My guess is that the right rear timing chain has slipped causing the rattle and low compression on all three cylinders. You can confirm that with a simple compression test.

 

[YountExplr]

I havent really noticed a loss of power at all. And the misfire was only yesterday morning. I will go get a compression test though. What should the compression be at?

 

[2000StreetRod]

Compression value

The SOHC V6 has a 9.7:1 compression ratio. The compression should be about 150 psi.