What is causing my rpm' s to drop in my 02 grand prix GT? It will run good then I'll stop at a light then it suddenly stalls
Bad or dirty IAC. (Idle Air Control) valve. When it stalls out, can you smell gas under the hood? A leaky injector could be causing your stall issue also.
A vacuum leak can and will cause this. Open hood and listen for a hissing noise if it will idle long enough. Rubber hoses break down and crack over the years causing cracks and leaks.
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