Two possibiliies come to mind. You could have a slightly undercharged system or it could be contaminated. The best approach would be to have a shop remove the R-12, vacuum the system and then refill with a measured amount. While the system is evacuated it would also be a good idea to inspect the orifice tube and if the system shows signs of contamination replace the dryer. On another topic if the mode switch is hissing rebuild it. With a leaking mode switch and the drop in vacuum on acceleration some of the actuater doors could be moving on you. David Teitelbaum vin 10757 --- In dmcnews@xxxx, "Walter Coe" <Whalt@xxxx> wrote: > > When you are driving, however, cool air flows nicely but > > when you accelerate, the cool air becomes warmer, and when you > > decelerate the air goes cool again. > > I'm mostly just book smart on this subject with little practical experience, > so take my advice with a grain of salt: > > When the air from your vents gets warmer, are you sure this is the case? Or > are you just losing air flow from your center vents ? (