[Whitson]

3 days in a row now I've cranked the truck, flipped the AC on, and within 30 seconds start to feel the idle get rougher and rougher until some loud injector knocks get thrown into the mix. Touching the throttle feels fine but as soon as it's back down, rough idle is back and the sharp injector knock. Turn AC off and everything goes back to normal. If I'm driving down the road and turn the AC on, theres no issue for the remainder of the drive. Seems to only act up when first starting and idling. What in the world could I look for? 2004 HO 6sp.

 

[ssteve]

Have your batteries load tested and clean your battery connections.

 

[cerberusiam]

Check the AC compressor wiring where it runs down along the AC lines, that year is susceptible to scuffing the wires and causing all manner of issues.

 

[STORMKING]

Check the AC compressor wiring where it runs down along the AC lines, that year is susceptible to scuffing the wires and causing all manner of issues.

Does that apply to 2006 models too? My AC works when it wants but works great when it does!

 

[rghavana]

Any codes?
Also I would check actual clutch/compressor/belt for mechanical issue.

 

[24hrsparkey]

Check the AC compressor wiring where it runs down along the AC lines, that year is susceptible to scuffing the wires and causing all manner of issues.

yes right by the oil filter area , those as clutch wires often chafff or melt and ground out intermittently

 

[cerberusiam]

Does that apply to 2006 models too? My AC works when it wants but works great when it does!

Not as common on the later trucks but it needs checked. This generally won't stop AC from working though, that is usually something else.

 

[STORMKING]

Hmm. Ok. It works all the time just gets cold or not cold, no inbetween. Rascal is a pia to figure out.

 

[Whitson]

No dice on bare wires, mine are fine.

 

[Whitson]

Now it's to the point that I notice a lope at idle with ac on. Goes smooth when compressor kicks off. Before the problem was only noticeable shortly after startup but now it seems to be constant. Anywhere else I can check for bare wires?

 

[PWong]

Now it's to the point that I notice a lope at idle with ac on. Goes smooth when compressor kicks off. Before the problem was only noticeable shortly after startup but now it seems to be constant. Anywhere else I can check for bare wires?

How about checking the harness connector right above the engine oil dip stick under the hood.:wink2:

 

[24hrsparkey]

Is it possible the electric clutch on the ac compressor is almost fried / grounded out when called to engage ( but still engages for now ) dragging that 12v circuit down . And could one test the clutch coils for this.

 

[PWong]

Is it possible the electric clutch on the ac compressor is almost fried / grounded out when called to engage ( but still engages for now ) dragging that 12v circuit down . And could one test the clutch coils for this.

IMO it likely possible.
I would check the current draw by the clutch to if anything out of norm and at the same monitor the driver side battery voltage.:wink2:

 

[Whitson]

The batteries are both less than a year old, no concerns there. I'll see what I can gather from the clutch, somehow.

 

[ssteve]

Checking the battery voltage is one of the simplest things you can do. I've seen brand new batteries that wouldn't crank a motor fast enough to start it. Good luck, hope you find the problem!

 

[tryNto]

Just because they are only 1 year old, doesn't mean they are good.
Maybe a corroded connection somewhere causing bad things.

 

[Whitson]

I bet you guys buy a bunch of batteries. Gotta be hell on them having them load tested every time ANYTHING out of the ordinary happens.

 

[rghavana]

Proper 10-20 second load test using real tester is not going to damage a good battery.
Run your 200 amp grid heaters in winter the batteries get load tested every time.

 

[Whitson]

Just a jab at how some point at batteries....for everything

 

[Blackduck59]

By the way your post reads this only happens when cold?
Maybe just too low on the idle speed and it is lugging when cold.