SHO runs rough when heater is turned on

[Blast7]

My SHO immediately drops at least 100RPM when I turn the heater on. It then fluctuates up and down in it's RPM around 100RPM or more there after. Sometimes it gets so bad that at a stop it will even stall out. When my heater is turned off the tach does not fluctuate 100RPM but you can feel the engine loping just a bit. It doesn't really show up on the tach at that point.

 

[projectSHO89]

Do you have a manual or an automatic heater control?

 

[Kevin Airth]

Check that the A/C compressor is kicking on and off. Sounds like it's draggin maybe? Get the A/C pressures checked, could be low causing too much cycling. Does the A/C work?
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[sdpatt]

If you are referring to using the AUTO setting on the climate control, the A/C compressor is being used also. It may be that you just need to reset the idle program. Read how here.

 

[Ishodu]

I have the same prob. I know its the AC compressor causing it. Likes to cycle just about the time ya go to pull away at a light or something Open the hood and check to see if the clutch is cycling on and off while the car is at idle.
Anyone know how to stop the compressor from doing this utill spring. I just dont feel like getting it charged up yet.

 

[projectSHO89]

Pulling the plug, either on the pressure cycling switch or from the clutch connector, will accomplish this.

Steve

 

[Blast7]

I'll check the AC compressor because now that you mention it the more I think this is the problem. I do hear a clicking noise like it engages once the heater turns on. I don't use the auto function and have already done the idle program procedure.