Every time I seem to have my heater on my truck kind of feels like its slipping, hesitating to shift or something like that. I can turn the heat off and it stops. Any ideas?

 

Are you using the defroster or defrost/floor setting, or is your A/C button on? If the answer to either of those is yes, then you may have an A/C compressor going bad. The temporary solution would be to disconnect the electrical connector on the A/C accumulator. That will disable the A/C compressor.

If the answer is no, then that is an odd issue you're describing.

 

Yes the defrost will do it but the a/c button is not on.

 

When you have the defrost mode on, the A/C compressor engages to dehumidify the air. Even though the A/C light isn't on, the compressor is engaged unless it's ***** cold outside.

So if the issue doesn't happen when you have it set to vent and/or floor, it's your A/C compressor failing. You can disconnect the electrical connector on the A/C accumulator for now until it can be replaced.

When a compressor begins to fail, it causes excessive drag on the engine. This will feel like a slight loss in power and late shifting from the transmission. The late shifting is because the engine is under a load. The engine can't tell the difference between a bad compressor and a load of bricks in the bed. It just knows that there's more of a strain, so the transmission compensates accordingly.

If what you're feeling is only slight, then that is totally normal. The compressor does create drag on the motor. But if it's a rediculous amount and your shift points are extremely high with a very noticable loss in power, then it's a bad compressor.

 

Ok i'll try disconnecting it. Where might it be located?

 

Also I looked up new ones and I'm coming up with 2 part numbers. Anyone know which one is correct?

Part #: MIYCC249
Part #: MIYC2557

 

Look for this thing on the passenger side under the hood.

http://www.napaonline.com/Catalog/Ca...(P_RecType%3aA)

There's a 2-wire electrical connection on it. Just unplug it.

I have no idea. NAPA only list one compressor type. They have it in two different brands. If you are going to replace the compressor, don't forget all of the other required items:

New accumulator
Orifice tube
Flush all lines, condenser, and evaporator
Correct oil
Check for any system leaks and fix them while the system is open

Have system evacuated and charged immediately after replacing. This will prevent the accumulator from becoming saturated with moisture. Never slap parts on and attempt to charge the system without having it evacuated. It's a critical step.

 

Also would like to know if the compressor has seized up a little would that cause the same symptoms even when unplugged?

 

Nope. The compressor has an electromagnetic clutch. Disconnecting the wires will prevent that clutch from engaging the compressor. When disengaged, the only thing you're turning is the pulley. The compressor itself isn't moving. Make sense?

 

The compressor will turn on in all modes except VENT..........

 

Ok makes sense. So the pulley will spin freely with it unplugged, so there is no resistance at all correct? So theoretically if i were to try and spin it by hand it would turn no problem?

The reason I ask this is because I'm trying to rule out all my problems. It makes sense that it created a much greater load with it on. Now my next question. My truck has been doing this for a while now, I guess I only noticed it with the air on. Now it still does this with it off, just no where near as noticeable. Yesterday when I was driving air was off, still havn't unplugged the compressor because it's in an awkward spot and hard to just reach up and unplug, i was pulling out of a parking lot and it seemed like my truck stopped running for a split second. I only noticed it because I can hear my exhaust pretty good. I was easing out and my truck felt like it was pulling back on me then for a split second it sounded like it stopped running then I gave it a little more gas and back to normal it was. Now i'm stumped, I really don't want to take it to a mechanic because I want to try and do it myself. I've already replaced all the plugs, the CoPs, cleaned the TB and MAF. I am trying everything and hopping it is not the transmission.

 

If you can't reach the connector on the accumulator to unplug it, you can test by turning the climate control system completely off.

 

Negative. On the 2004-2008 trucks, there is an AC button. As long as that button is off, the compressor will not engage. The only exeption is when the defrost or defrost/floor mode is selected.

 

Correct.

In that case, you probably have a different issue. Having the AC on (or anything that causes the compressor to load the engine) will simply amplify other problems.

With that knowledge, it's time for the basics. Have you had the truck scanned for any check engine codes? You don't necessarily have to have the check engine light on for a code to show up. If you don't have a scanner, Advance or Autozone will scan your truck for free. If you find any codes present, let me know and I'll try to help troubleshoot from there.

 

I had it scanned when the CEL came on, and at the time I thought the reason was a bad plug or CoP because it felt like it was misfiring and it was. I replaced all 8 plugs and CoPs and no more CEL just these symptoms now. I guess the best way to put it is if I try to accelerate slowly it feels like its pulling back or slipping. I give it more gas and it stops or if I accelerate quickly it wont do it, also it feels like its doing that sometimes when I keep it at a constant speed like around 55 or 60ish. Sometimes it will do this and another time it won't do anything at all and seem like its fine.