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RussMasterTech
RussMasterTech, ASE Certified Technician
Category: Chevy
Satisfied Customers: 791
Experience:  19 years of GM Dealership experience. ASE Master with L1 and GM Master Certified in Electrical
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I have a 1999 Chevy Tahoe which spits, sputters, bucks and ...

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I have a 1999 Chevy Tahoe which spits, sputters, bucks and pings from the engine when it gets hot out and the engine warms up. To date the service engine soon light has only came on intermittently but no code is present when placed on a diagnostic. The symptoms get worse and worse to the point of stalling and not being able to restart. If I pull over to a parking lot and turn off the ignition for several minutes, it will restart and I will be able to drive normally for a couple of miles until the symptoms start all over again. While it is cool out now there has been only spurattic sputtering but when we went on a mini vacation a few weeks ago when the weather was in the 80+ range we were plagued with this problem. Upon return I had the radiator and tranny flushed and serviced. The oil only had 2,000 miles on it and it was the thinnest I ever saw it. I drained it, changed filter and the problem was solved. Now the vehicle only has about 1,000 miles on it and it is bucking again.

Hello,

How long ago did you replace the distibutor cap and rotor?

This is the most common issue on concerns like the one you are describing.

If you installed a cheaper non OEM cap, I've seen them fail much quicker than the OEM's. The aftermarket caps have a tendancy to burn through the terminals and then crossfire to the wrong cylinder which would cause all of your symptoms.

You may also want to check the fuel pressure while it is occurring. When running, the fuel pressure should be 52psi at idle and about 64 psi when the engine is revved up. I've heard a few people that have had fuel pump issues with the temp over 80 degrees, but usually, the truck will just stall, but I suppose if the pump were just binding and not completely locking up, it could cause a lean condition which would account for your symptoms as well.

There is a bulletin from the factory about the crankshaft position sensor being the source of intermittent driveability issues as well.

Hopefully the distributor cap will fix the concern, but let me know.

If this has answered your question or has helped you, please make sure to click the "Accept" button so I may receive credit for assisting you today. Positive feedback would be greatly appreciated.

Thanks for using Just Answer.

Russ

RussMasterTech and 6 other Chevy Specialists are ready to help you
Customer: replied 8 years ago.
Reply to RussMasterTech's Post: Could you advise where the crank positioning sensor is located? I know for a fact it cannot be the distributor or rotor. I drove the truck today and no problem. It has to be the Crank Sensor. One other symptom the vehicle has is the rpm gauge is spuratic with its readings. At idle it reads 0 and while accellerating it goes to 6000-1500-0-3000. It is all over the place and not what the actual Rpm is. Is the rpm attached to the crank sensor also?

The crank sensor is in the front timing cover on the passenger side of the engine. Check the wiring for chaffing as this could be causing it also.

Hope this fixes it for you.

Russ

Customer: replied 8 years ago.
Reply to RussMasterTech's Post: I will get back to you after I try it.