QuestionQUESTION: 2002 GMC Yukon SLT w/ 5.3 vortec has a ruff idle(especially after warm up and has bad exhaust smell(sulfur type odor)what could be the causes?
ANSWER: HI ROBERT,CK THE BACK SIDE OF THE THROTTLE PLATE, IF ALL CARBONED UP CLEAN IT OFF WITH CARB CLEANER AND A [SOFT]BRUSH AND USE YOUR FINGER..IF NOT, CK FOR A VACUUM LEAK AROUND THE INTAKE WHERE IT MEETS THE HEADS. SPRAY THE AREA WITH CARB CLEANER,IF THE IDLE SMOOTHS OUT YOU FOUND A LEAK.GET BACK TO ME IF NEED BE. HOPE THIS HELPS YOU AND GOOD LUCK,,,TOM
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QUESTION: Yukon does have 140k mls on it! I did have to remove a mouse nest from under top cover/shroud of engine right about the time this started also! FYI
Thanks for input!
ANSWER: HI ROBERT,YES MAKE SURE THERE ARE NO OBJECTS BEFORE OR AFTER THE MASS AIR FLOW SENSOR AS WELL.
GOOD LUCK, TOM.
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QUESTION: cleaned plate..very dirty..looked clean and clear....sprayed around the area stated , but no real change! Hesitation on acceleration! revs and looses power back to idle...still ruff and odor from exhaust really not apparent till hot?
Oxygen sensor? Catalytic converter?
Check Engine light on continuous! Maybe a valve?
Was told #6 cylinder was loading up? Throwing everything off obviously!
AnswerHI ROBERT I DID NOT KNOW YOU HAD A CK ENG LIGHT ON..GET THIS SCANNED, IF IN FACT IT IS A MISFIRE ON # 6 COULD BE COIL PLUG OR VALVE..THIS WOULD EXPLAIN BAD SMELL,, RUNNING ROUGH AND SO ON../ LET ME KNOW WHAT HAPPENS AFTER SCAN. A BAD CAT WOULD NOT CAUSE A SKIP,IF PARTIALLY PLUGGED IT WOULD HAVE A LACK OF POWER ON THE OPEN RAOD. THIS IS NOT A BAD O2 SENSOR EITHER. GET THIS # 6 DIAGNOSED....GOOD LUCK TOM.
