99 tahoe drivetrain problem????

[boatman]

can't figure it out, 99 tahoe with 160k, at 75 and above it feels like it surges or backfires no sounds, but it seems like it jerks. have given tune up, and new rebuilt trans. It only happens when you let off the gas and hold speed. dealerships can't figure it out and no error codes. PLEASE HELP!!!!!!!!!!

[Bubbass]

Originally Posted by boatman

can't figure it out, 99 tahoe with 160k, at 75 and above it feels like it surges or backfires no sounds, but it seems like it jerks. have given tune up, and new rebuilt trans. It only happens when you let off the gas and hold speed. dealerships can't figure it out and no error codes. PLEASE HELP!!!!!!!!!!

Reply-Bubass; Your 1999 Tahoe Has one of two issues that are not code related items #1- check to make sure your EGR vale is working properly. The unit has a coil for the valve and a sensor if the sensor is working and the coil isn't no fault codes will appear tjis requires EGR replacement cost around$225.00. #2-check fuel pressure check with the dealer for the psi and you will need a fuel pressure tester availiable at you local auto parts dealer. I have a 2000 Tahoe and it was a combination of both of these issues and alot of headache involved in finding the problem without becoming a parts replacement technician. I hpoe this works.