Still having erratic starting problems so I need some opinions please. My picku on 2004 Chevrolet Silverado 1500

p is hesitant to start except on cold days or the first start of the day. After a day of stop and go errands or when the weather is really hot it may take as many as 4 cranks before it kicks over. It runs like a scared rabbit once it starts. No engine light, no hesitant acceleration, no engine light on, no codes when scanned. Do I get bad gas mileage? Well, gas prices are out of site, I drive a V8 crew cab and live in Houston, Texas. Anyway, I do not or have not seen any huge fluctuation in my fuel consumption. Here's the kicker--it has been doing this for 5 years. I had one vacuum leak-fixed it, I've changed all relays, fuses and the ignition switch. So I decided it must be the fuel pump but after 5 years it seems like it would have quit on me by now. I've been every where and talked to everybody about this and still have no solution. What do you think?

by in Houston, TX on March 17, 2013
2 answers 5 comments
ANSWER by on March 17, 2013
you did not mention spark plugs. have you tried changing them at all(5 years)? it could also be a vapor lock in fuel system. is not a common thing but more likely in your climate, especially when the engine is already hot. i am guessing it starts better when ever engine has had time to cool down sufficiantly.
COMMENT by on March 17, 2013
Yes spark plugs have been changed several times. The last time was just last week. Fuel pressure is fine so would it or could it still be a vapor lock? As far as it starting better once engine cools down not necessarily when I've been driving it all day. Basically, once it starts requiring 4 cranks to start that is the way it will be the rest of that day.
COMMENT by on March 17, 2013
if driving steady all day it would take a couple of hours for the engine to cool down enough for gasses to re condense. spark to fuel works when fuel is in mist form, not vapor. fuel air ratio is offset. fuel pressure looks normal because it actually reverses(back pressure in fuel system). it gives a false reading. like i said, not a common prob. but some thing to look at. (especially in a hot climate).
ANSWER by on March 17, 2013
If you press the gas to about half throttle or wide open throttle when starting will this help? If so post results and we will try to be of more help. Also shop can hook up a pressure gauge, run it under hood tape it to the windshield, as long as forcast not calling for rain, so driver can moniter pressure on hot restart. Need to know this! Pressure will take care of any vapor problems if correct.
COMMENT by on March 17, 2013
I will try the half throttle method. I have had several pressure tests run. All returned okay. However, I have not had it monitored throughout the day. I will check into that tomorrow. Have any idea what a shop would charge me to do that? My husband said he can hook up a pressure test himself. Is there a pressure valve hookup on the fuel rails?
COMMENT by on March 17, 2013
No but if you know a mechanic should not be that much IF part of a future repair for him. We do this a lot at the shop as we dont have time for a lot of test driving that the customer wants to pay for. But i am in rural Va. also so you know.... There is a test port on the engine but you did not say which. I THINK the 4.8-5.3 and 6.0 are on the passenger side fuel rail 4.3 is on the drivers side rear of the t-body. Cant remember right now but all have one.
COMMENT by on February 16, 2015
I'm having the exact same problem with my 02 Silverado 5.3. I also live in Texas...about 6 hours from Houston and my truck has been doing that same thing for a few years! The only thing I've found that helps is to turn the key on and off a few times to build up the fuel pressure- then it usually starts on the first crank. Every once in a while I have to crank it 2x before it starts after building up the pressure. Like you said, if it was the fuel pump...it would've stopped by now. I've read other forums and someone said that it may not have enough pressure to start, but has enough to run. I think they said their pressure was reading 50psi, but the engine needs 57psi to start. So either the fuel gets too hot and "evaporates" or the pump deosnt have enough pressure. Wich doesn't make sense, because it would either work or it wouldn't....especially for the years we've had this problem. Just a thought and I'm about to go check, but I removed my air intake to replace my knock sensors and I had to relieve the fuel pressure at the Schrader valve (passenger side above the fuel rail). (I also cleaned off my fuel injectors while the intake was off) but mu thought was maybe the Schrader valve is loose causing some pressure to release, thus having to turn the key off and on to cycle the fuel pump off and on to rebuild the pressure. The Schrader valve is the exact same thing as what's on your tires btw. Well I'm going to go make sure it's tight and see if it helps.