jallen72

My 99 Tahoe does not start easily. It will turn the engine backwords for a few turns when you disengage starter. Once it starts it will run pretty good, except for a hesitation as the automatic transmission shifts and even greater hesitation and slight backfire when accelerating at 55-60 mph. I replaced the following as I had codes for each: crankshaft position sensor, right front oxygen sensor, and coolant sensor. I am inclined to believe it is a fuel pump problem even though I replaced fuel pump with a less expensive model from Advance Auto a couple of years ago. I have also been reading a number of forums pointing to the fuel pressure regulator and possibly the fuel filter as possible culprits. Note: My wife attempted to start the Tahoe a week ago and it backfired so bad it blew the muffler apart. I plan to replace muffler but really need to fix the other issue before destroying another muffler. I plan to purchase a fuel pressure gauge today and test my pressure, but how do I know for sure if it is the fuel pump or the fuel pressure regulator? Also, my gas tank is nearly full, how do I remove the fuel so the tank is light enough to lower and raise easily? I can't muscle it up anymore as I have had shoulder surgery and neck nerve issues. Both of these fixes cost more money than a sensor, so I want to be sure to replace the right part. I had a tune-up at the garage about 8 months ago when I was working at a job I could afford to hire my work done, that is no longer the case and I must do this work myself to save $$$.

jallen72

Finished pressure test. When key is on and engine not running my psi is 58. When idling the psi is 52. I did notice it took some time to bleed off the air in line. I was told should be 60-66 key on, and engine idling. I don't know if this is true or not. Based on what I have read it appears to be fuel pump. Agree or disagree? I have not replaced fuel filter yet, do you think changing that might make the difference in pressure?

RichC10

That pressure is fine, 50-55 is all you need. It should maintain the pressure in the line with the engine off. The fuel pump is not your problem, and if it holds pressure, the regulator sounds good too. What condition are the spark plugs in? Fuel filter replacement couldn't hurt.

jallen72

The pressure does hold. I had codes for a misfire at #2 cylinder so I replaced that plug only and when I did I found the wire was not crimped properly so I fixed that. I have not pulled the plugs to look at them, I have been stuck on thinking it was a gas issue, because I had a tuneup done at garage about 2 years ago. I will pull plugs, replace and change the fuel filter as well. Thanks for your advice, any and all help is appreciated.

73shark

Be sure to use the recommended AC Delco plugs. These trucks don't seem to like other brands.