I have a 1999 chevy Blazer it starts all right but during acceleration it stumbles , jerks , the tachometer drops down to about 400 rpm but does not completely die . The tach. comes up when you let off the gas .It does this in cool weather fall and winter not so much in spring and summer , it goes away after engine
is completely warmed up .
JA: Has the vehicle turned into a gas hog? And how does it start -- same as usual?
Customer: No its does not use any more gas than usual . it starts fine .
JA: Are you fixing your Blazer yourself? What have you tried so far?
Customer: I have taken it to a dealership and two other smaller shops they say it does not do it for them , It has no check engine lights . I bought a scanner and it shows no codes .
JA: Anything else you want the mechanic to know before I connect you?
Customer: I have changed the throttle position sensor and the MAP sensor in the intake manifold so far.