2003 Chevy Silverado won't start on the first try

Hello. I’ve been having this problem for a while now. Specs: 2003 Silverado-1500 with 260,000. New wires, plugs, fuel filter. I clean the Throttle-body and Mass-Air-Flow Sensor every two weeks. I use Techron fuel additive @ every fill-up. I have also tried using Seafoam Motor Treatment in the tank and crank-case. It turns-over but won’t start. I have to try 3-4 times before it starts. The only time it starts on the FIRST try is when the gas tank is FULL. What do you guys think?

Try checking fuel pressure.

Sounds like you maybe “priming” the lines because fuel is back flowing out the fuel pump. This happened on the Escort. Just a theory but never know.

Harland, Thanks for the feedback. I don’t touch the gas-pedal when starting the truck. So, I don’t think it’s an issue of “priming the lines”. I will say that I’ve tried pumping the gas-pedal a few times in the past, but it had no-effect on the issue.

NCCXMAX if you cycle the key multiple times (or attempt to start a few times), you ARE priming the iines.

Every time you cycle the key, you are energizing the pump

I think it DOES sound like a possible fuel pressure issue

This is another vote for fuel pressure problems.

@db4690 thank you for explaining my theory more:)

missilman in theory pretty much when you turn your key to ON engine OFF the fuel pump activates and gets gas into the line to build up pressure. On my Escort my lines would go bone dry (literally) after turning off the car because fuel would flow back out the pump.

The fuel check valve leaking fuel back does seem to be the logical problem. I’m not sure why you clean the fuel system so much. I could see maybe every few years possibly. Todays fuels have cleaners mixed in already. At least the top brands do.

Have you tried leaving the ignition on for a bit, maybe 10 or 20 seconds to see if the problem goes away? If so probably a fuel pump.


I agreed with you and really just wanted to jump into this conversation

If not the fuel pump my next guess would be the coil pack. To test it disconnect the wires, if they are like the ones i’ve tested in the past there will be three wires but only two colors, one for the common and the other two for each side. With the meter set to OHMS touch one prob to the common and the other to one of the sides and repeat on the other side. You should read at least 1.5 ohms per side.

If OP’s truck has the V6, it has a coil pack

Otherwise, it’s coil on plug

My 2007 Cobalt as the same symptoms , when the tank is full it never starts the first time.
Has me stumped , any help out there?