Hello everybody


My 00 GMC Jimmy run rough at idle and especially when I shift to reverse the car rpm drop down and there was a rotten egg smell coming out of the exhaust this problem from the time that I bought the car until now. I hear that it could be a bad brake booster and today I test it by plug the vacuum hose that goes to brake booster check valve and I run the car and it is run very smooth then what it was during all of these years.

My question is how can I know if the brake booster check valve is bad or the brake booster it self is bad ?

thank you

 

George