sputtering

**99PTA** · 07-16-2007, 03:20 PM

I have a 99 silverado and am wondering what the fuel pressure is suppose to be. The truck is sputtering when going up hills and seems to do it whenever giving half throttle. I have given the 5.7 a tune up with plugs, wires, fuel filter, and wonder if the fuel pump is on it's way out. Also do any of you know how many old style 99's were made.

**Naf** · 07-18-2007, 04:48 AM

If memory serves me right, 99 pickups had the 5.3 vortecs, not the 5.7...

Now would you discribe this sputtering, does the power come and go after a certain rpm, or is it just under load...I had my share of pump failures and trust me it aint pretty, the engine has that feelin of dyin at any moment....On the 5.3 there is a nozzle inwhich you may check the rail pressure, on the vortec it should be around 58psi, but if you have a LT1 No clue, a TBI i think 10 or 22psi "I THINK"...

**dozerdan** · 07-18-2007, 02:42 PM

his is a 99 classic....with the 5.7 votec.

**99PTA** · 07-19-2007, 06:49 PM

yeah its a vortec 350 I think they only made them for the first few months in 99 before changing to the new style. I checked the pressure and its sitting at 50psi. It surges when under load like when I'm going up hills. The truck has 90k on it so I figure it still has the original fuel pump.

**Naf** · 07-20-2007, 12:26 AM

if it surges then it is your fuel pump.

Ther are reasons why the pumps fail, some are just purely age, others are runnin on an empty tank, or too much junk in the tank...

When you change the pump, insure they flush the fuel system...It would be better for you in the long run...