Anyone know why 2009 Camry 4 cyl runs rough when ac is turned on? Car has 42k and started during last 6k. Dealer says car is normal but it didn’t do this until recently. Any help will be greatly appreciated.
That can be caused by the obvious things or by a really bad ground between engine and body. Run a jumper cable from one to the other and you will find out immediately if the not-so-obvious is or is not the problem.
When you switch the AC on in idle, does the idle speed drop? If it is doing that, then there is a issue with the idle control system. It could be a defective IAC (idle air control valve) or something as simple as a dirty throttle body or something keeping you gas pedal from returning to full height when you take your foot off the gas.
I believe Keith is correct. We have a 2002 Camry and several years ago it also idled rough when the AC kicked on. The IAC valve was the culprit. Look at your tach when the AC compressor kicks on. If the IAC is bad, the engine speed will drop approx.100 RPM or so.