1997 Toyota 4runner- a/c running - low side of the system- hooked up a gauge- with the compressor running- reading is approx 25psi - when the compressor cycles off the pressure jumps to approx 40 psi - what is the suggested readings? Should I relieve any pressure? added about a can and a half of R134 last night- air blowing was a little warm- with the added R134 we have air coming out between 39 and 41 degrees- right on spec.... thanks!

 

Low side sounds ok. It's hard to know the whole picture without the high side pressures though. But with your air temps I'd say your not too far off.

 

My A/C wasn't blowing very cold in my 2000 4Runner, and I tried adding a bottle of the "A/C Pro Refrigerant" and now the system just vents out and doesn't blow any cold. Suggestions? I need to get this fixed because it's my wife's truck, and she needs the air.

 

Was it real refrigerant or some cheapo substitute mix? You can irreversably damage your A/C compressor with overchartging or putting in some junk.

I'd say it's broken. If it's blowing ambient temperature, it's very broken.

Seek professional help. A/C systems are a little more complex than doing a tire rotation.