Engine stuttering

I have a 1997 Blazer LT w/ engine code w. My problem is when I have my defroster on, the truck seems to stutter a-lot. As soon as I shut off the defroster it clears up. Now, i'm pretty sure that's not normal but my last vehicle (a Ford Explorer w/ 190,000 miles) did the same thing. How do I fix this or is thois something I just have to live mith. Thanx in advance, Redneck :banghead:

Defroster uses the AC compressor to dehumidify the air.

Are you using the fan full blast while doing this too?

If so, don't do that.

Defroster uses the AC compressor to dehumidify the air.

Are you using the fan full blast while doing this too?

If so, don't do that.

No, it does it with the fan on low or high. It doesn't seem to matter what setting it is on. Could it be low on freon?

With the engine running and the defrost on, check under the hood. Is the compressor engaging on and off quickly? If so, the freon charge is low.

It could be that or the compressor bearings are gone and the engine is struggling to rotate the compressor.

Usually the belt gets smoked up at that point.

Not always.

The compressor bearings might not be completely shot and the belt is probably a good one that is not allowing the slip.

Not always.

The compressor bearings might not be completely shot and the belt is probably a good one that is not allowing the slip.

Yea, the compressor goes on and off anyware from 27-35 times in a two minute period. There is a slight whine from something on the engine but I can't pin-point it.

Yea, the compressor goes on and off anyware from 27-35 times in a two minute period. There is a slight whine from something on the engine but I can't pin-point it.

Ok, do this for me, disconnect the electrical connector from the top of the compressor and leave it unattached until you fill your A/C system again.

The compressor going on and off like that is a sign of low refrigerant.

Remove the electrical connection or BYE BYE AC system.

I am not joking, DO IT

Ok, do this for me, disconnect the electrical connector from the top of the compressor and leave it unattached until you fill your A/C system again.

The compressor going on and off like that is a sign of low refrigerant.

Remove the electrical connection or BYE BYE AC system.

I am not joking, DO IT

No problem. I'll fill it tomorrow. Should I put the combo sealer/oil/freon in it or just a freon/oil charge can?

freon/oil only unless you expect a leak which I doubt.

You sure you know how to do it properly?

freon/oil only unless you expect a leak which I doubt.

You sure you know how to do it properly?

Yea, I did several on my Explorer. The kits are pretty self-explanatory. Thanks for the input :biggrin:

With the freon and oil topped up, the compressor cycling should stop.

With the freon and oil topped up, the compressor cycling should stop.

Sorry it took so long to get back, my mother-in-law had a heartattack. I filled the ac up and it quit cycling so much. I still have the stuttering prob. Tune-up done 3 weeks ago. Any more input? :banghead:

What did the tuneup include.

What did the tuneup include.

Plugs, wires, cap and rotor and fuel filter as reported by dealer. But you know how that goes.

PCV valve.
Air Filter

If it stutters under a load, sounds like a spark plug, plug wire, or distributor cap. Try popping the hood on a dark night and look for fireworks.

That or the coil is failing.