Chevy Tahoe Missfire

JrSyko

Jerry Maguire
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My mom has a 99 Chevy Tahoe with 40,000 miles on it. Cylinders 4, 5, and 6 have miss fired 700, 1600, and 500 times respectively. She will be driving, and I have had it happen to me too, and the car will just lose all power. We will be doing like 25 mph on the freeway until it stops. The car has a 3 inch flowmaster and a K&N generation 2 intake on it. Has anybody else had similar problems? Could it possibly be getting too much air? Any advice would help as all the mechanics we have taken it too have had no idea of whats wrong.

See ya in the dirt!
 

blind655

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when you installed the intake did you disconnect the battery? I was told to do that to reset the trucks computer to adjust to the increased air flow. If you try it unplug the negative cable and let the truck sit for 30 min. Does the check engine light come on when this happens?

A suburban might not be as good as a truck, but it comes damn close with 8 people in it
 

JrSyko

Jerry Maguire
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I'll try that, but I did unplug the battery when I installed the kit because it called for it in the instructions. And to clearify, you mean unplug the battery after the instal is complete?

See ya in the dirt!
 

BradM

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My dad has a 98 tahoe with a 350 that has had an intermittent misfire. It would usually happen under load like climbing a steep grade. The problem was traced to the heads. It seems the valves were hanging up in the valve guides when under load. This has been a common problem with many late model 350s as the same problem was also happening on his 2000 chevy 2500 work truck with a 350. The solution was to pull the heads and ream the valve guides and replace the seals.
 

blind655

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if u you did that when you installed it then its ok

A suburban might not be as good as a truck, but it comes damn close with 8 people in it
 

Ryno

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Brad-

the vortec heads are in a service bulletin for this. I don't have the # right off hand. I have also seen the coil paks arc between themselves, causing a misfire under load. I would try to reset the ECM. It should throw a code if it happens that much. Then it's self explanatory.

Ryno

Build it like a Rhino, and Leave it be.
 

Greg

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My dad has a 98 z-71 that would miis-fire when pulling a trailer or going up a steep grade, after doing all the "regular" stuff he took it back to a local dealer and they replaced the heads for free and the problem was gone. I really didn't think it was sticky valves but it was.

Greg
 
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