Car keeps hesitating while AC is on....
 

I drive a 96 honda civic 5-speed. I just added R134A to it. Whenever i run the car with the AC it seems like my car will accelerate on its own and break on its own when i let off the gas, would any of you have any idea why this is happening??

Possible explanation: The ECU ramps up the idle when the A/C compressor clutch engages and lowers the idle when the A/C compressor clutch disengages.

With that said, did you measure the refrigerant pressure on the high and low sides to ensure that the system was not overfilled with refrigerant?

well first off if the pressure on the high and low side on the ac system correct or not?
if you just added coolant and dont know the correct pressure on the high and low sides then you could have a heavy load on the ac compressor that will hold the motor back and when the compressor kicks out of course the motor will feel like it has more power.

I bought the coolant that comes with the guage, so i didnt under or over fill it, it sits right at 35PSI


** what do you mean by high and low side??

Does the A/C work fine? Does the condenser fan run when you push the A/C button? I assume you hear the compressor clutch turning off and on when you push the A/C button.

If condenser fan runs:
You added refrigerant to the low side coupling. There's also a high side coupling. A manifold gauge set hooks to both couplings so that you can measure refrigerant pressures on both sides. You need both values to troubleshoot your problem.

yes the AC works fine, it dropped from 70 degree to 60 degrees after adding the refrigerant

okay im kind of confused. i added it to the the low pressure port, so you're saying there is a high pressure port as well that i need to add it to?

Nothing is ever added to the high pressure side coupling. It's there only to take pressure measurements of the high side of the A/C system. Having high and low side pressure measurements will tell you whether there is anything wrong with your A/C system. You need a manifold gauge set to make these measurements.

ive used those do it yourself inline gauges also.... in short THEY SUCK!!!!!! not accurate at all! thats why its best to pay the real AC guys to check it all out and fill it properly.

i appreciate the help guys. so how much would this cost?
where can i get a manifold gauge? and where do i hook this up at?

sometimes you can rent them at autoparts stores. i know that harbor freight has them for $39.99; I plan on renting them when I have to do my own work. btw, adding too much refrigerant will make the car hesitate at idle or whenever the compressor engages.