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I have a 1999 Chevy Tahoe w/ Vortec V8 5.7 L engine. I have a problem that has been going on for about 4-6 months. Vehicle starts right up when cold. It also starts right up after being driven and it is fully warmed. If it sits a short period of time and cools a little, it has to crank longer than normal to start. It recently had a tune up with air & fuel filters, spark plugs, and PCV valve. I took it to the dealer, but they could not find anything wrong. There were no codes stored, and I have not gotten a "check engine" light. They did comment that it might be something with the fuel system. Any ideas?  

I had the exact same problem.  Starts up perfectly when cold or after sitting long enough for the engine to cool. Actually it had nothing to do with the engine temperature.  It was the extra fuel that was leaking into the intake. Unfortunately, it happened to me years ago so my memory of the exact part is slipping me. Had no luck finding the problem. (And I usually do all my own maintenance) So, I went to a relative, owns his own shop. I believe it was the fuel pressure regulator. A ruptured regulator diaphragm will pass fuel to the vacuum hose and into the intake manifold.  The gas that leaks into the manifold "floods" the engine on the restart.(in lay-man's term's) Cause you to have to crank the engine over longer to burn off the extra fuel and what was getting dumped in by the injectors. The engine would only start fine if there was enough time for the fuel pressure to be released and enough evaporation occured. Hated the problem, but after he replaced fuel pressure regulator, I was back to norm.   Hope this helps.  

It could be the fuel pressure regulator. It can be letting the pressure go after a few minutes which will make it harder to start. My 99 Silverado had that same problem along with some bad missfiring. When I replaced the old regulator the problem was fixed. A few other people I know had the same problem and it fixed it for them. Problem is the next day (only to me) the problem came back. I dont know if the regulator broke again or what the heck happened. I know my fuel pump is old and whines but if its old and supplying too little fuel i dont know how it could have broken a regulator. I dont really know. If anyone does please let me know.  

I just fixed the same problem on my '99 Tahoe with the 5.7 Vortec. I had replaced fuel filter and pump and still had slow starts.  I replaced the fuel pressure regulator and that fixed the problem.  Only sucky part is on our engine it is located inside the intake manifold so the top plenum (as well as the birds-nest of wiring and hoses) needs to be removed to fix it. You also should partially drain the radiator so you can remove problem hoses as well.  Took about four hours, $130 in dealer parts (fuel regulator, and manifold gasket kit).  

Thanks for the replies. I changed the fuel pressure regulator and it has seemed to fixed the problem. It's been running about a week since I did the work. Plenty of time to check it out, and it starts fine now.

Steve is right about the replacement job. Took me about 4-5 hours. Good thing I have the service manual to lead me thru it. I originally did not know that it was under the upper intake manifold. I also had to remove the wiring harness and partially drain the radiator. Might have got away without draining, but it did make it a little easier. Cost me about $50. I did not replace the gasket on the upper manifold. Hope that wasn't a mistake. It looked in good shape. It may have been changed by the dealer when I had a lower intake manifold gasket leak a couple of years ago.

Thanks again for the advice.  

I've been experiencing this problem on my 1999 Tahoe almost a year.  As you all know this can be a very frustrating and elusive issue.  What you describe is exactly what I'm experiencing so I have to believe the fuel pressure regulator is the culprit.  One question, is there a visible defect in the pressure regulator when this occurs?  I may take it to my mechanic simply because I don't have half a day to work on it right now. I'll post again after the work is complete.  Thanks to all - your comments were a huge help!  

A further question:  Did any of you have your fuel pressure checked at the shop?  If so did it indicate the fuel pressure regulator was defective?  I had my Tahoe in the shop today and the mechanic (who I trust) said there was no indication that the fuel pressure regulator was failing.  But the problems you have described is what I'm experiencing.  That is why I ask if a typical fuel pressure test would indicate a problem?  Thanks!  

I have a 98 Tahoe with the 5.7L 350 and 150,000 miles.  It is doing the exact same things that you guys describe as well as an occasional back fire from the intake manifold.  I took it to the dealer a while back and they said I was loosing fuel pressure from the intake.  This sounds consistant with the bad fuel pressure regulator.  The dealer wanted to change all the injectors to the "new model" type.  I did not have the work done at that time.  I think I will attempt to do it myself.  Should I change the injectors as well as the fuel pressure regulator while I have it all apart.  Can anyone recommend a good manual to get.  Thanks -will  

I have a 1999 Tahoe Vortec 5.7L engine. My problem was the engine would not start when cold. Over a few weeks the problem got worse and would not start back up after a 1 hour shopping stop. I purchased and replace a new pressure regulator. It started right up after replacement.  I did not replace any manifold gaskets, as they were replaced a year ago when the intake had a leak.   I still need to wait about a week to be sure this was the resolution. On the 5.7 engine, you have to remove the top intake manifold (plastic) 1) Unclip all wiring harness 2) de-pressurize fuel) 3) Remove gas inlet tube clamp on back of engine 4) remove all fuel connections 5 )Remove cables for carb 6) No need to remove coolant to intake. 7) remove all intake bolts & ditributor wires. 8) Pry off intake from the back. 9) replace pressure reg by the clip.

Whole job took 6 hours to take down, 1.5 to put back. Cost was $62.  Hope this helps.  

Thanks for the much researched help, down here in Baja, 150 tho on my tahoe and it did exactly what you described.  Transalated the data on how to pull it and put new one in in Spanish, and will be on the road home shortly.  I did use starting fluid to get going on one occaision, but now will have it figured out totally.  Hopefully it was the problem, but sure does sound like it!  

Fuel pressure regulator made no difference, will put it on the scanner and see what code I get now that I am back up north.  It would never start up until cool but a bit of ether did the trick when an emergency start was required. Car surged a bit on the hills, but still made it!  

my problem is that it wont start cold at all unless i use starting fluid then it will run but boggs out around 3000rpms when floored. once it warms up it starts ok but still has bogging issues