4 Cylinder Surging when Heat/AC on

[RDay]

I recently purchased a 96 ranger 4cyl/5speed. It runs great until you kick on the AC or heat. The truck seems to stumble slightly each time the AC compressor cycles while the heat is on. The compressor seems to cycle on/off about every 30 sec while on heat but stays on pretty constant while on AC. I have seen a lot of post suggesting the IAC can cause idling problems could this be my source also?
Thanks in advance.
Rob

 

[Wicked_Sludge]

you could try cleaning your IAC.

you may also have some problems with your A/C charge level. does the A/C blow nice cold air?

a vacuum leak leading to the HVAC controls may also be a possibility.

 

[RDay]

Thanks for the reply.
The AC does seem to blow cold air but not really sure it is as cold as it should be. As long as the ac compressor is not cycling the surging is not present so I will look for a vac leak tomorrow.
Thanks

 

[Bryan22]

I don't know how bad it runs with the A/C on, but with my 94 I can deffenitely tell the a/c is on. truck idles down just a bit and runs a touch rougher. I just though it was normal since the truck isn't exactly a powerhouse. lol.

 

[Wicked_Sludge]

if the A/C system is not properly charged, it can put excessive drag on the engine when the compressor engages, causing rough running...even belt squeeling or stalling.

 

[prefab08]

i have the same problem with my 1999 and the air is ice cold , i just figured it was cause the truck has 190000 miles. so hopfuly you guys get some goodideas going.