CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Rough Idle _ Mazda Protoge

2003 Mazda Protoge starts and runs good, with exception of idle at red lights, etc. Idle gets very rough to near stalling. I changed plugs and air filter. Any suggestions?

Rough idle with a warm engine is generally the result of a vacuum leak.

Could be a vacuum hose split or disconnected, a failed intake manifold gasket, a leaking EGR valve.

There are other possible causes besids vacuum leaks, and other sources of vacuum leaks, but that is where I would start looking.