99 jimmy- 88,000 mi- 4.3- auto trans; New
lugs, wires, dist cap, rotor, and air & fuel filter at 77,000 mi. It has developed a stumbling hesitation, during vehicle warm-up. It occurs between 1300 to 1900 rpm. Very noticeable in the lower gears, as it approaches and enters shifting range. The problem seems to disappear after drive train warm up (while driving and 5 to 10 minutes AFTER reaching engine operating temperature).
Now my wife says, (and she's never wrong), she noticed the symptoms months ago, after I did an a/c flush and compressor change out. At that time I also changed out all vacuum hoses that I could find, in engine area. To my knowledge, trans fluid has never been changed, but looks clean and is within dip stick range. Shows no trouble codes on obd 2. I spent a little time tugging and checking wires and vacuum lines in engine compartment.
I will start by vacuum testing. Not sure where the best vacuum access is, or what the numbers should be. Any and all reply's are appreciated. Thanks in advance.
lugs, wires, dist cap, rotor, and air & fuel filter at 77,000 mi. It has developed a stumbling hesitation, during vehicle warm-up. It occurs between 1300 to 1900 rpm. Very noticeable in the lower gears, as it approaches and enters shifting range. The problem seems to disappear after drive train warm up (while driving and 5 to 10 minutes AFTER reaching engine operating temperature).Now my wife says, (and she's never wrong), she noticed the symptoms months ago, after I did an a/c flush and compressor change out. At that time I also changed out all vacuum hoses that I could find, in engine area. To my knowledge, trans fluid has never been changed, but looks clean and is within dip stick range. Shows no trouble codes on obd 2. I spent a little time tugging and checking wires and vacuum lines in engine compartment.
I will start by vacuum testing. Not sure where the best vacuum access is, or what the numbers should be. Any and all reply's are appreciated. Thanks in advance.