rough starting

I have a 1999 Silverado 1500 LT with 47000 miles. I just bought it from an older guy who hasnt driven it much in three years since his stroke. OK, heres the problem... when starting (not every time) I have to crank it over for a few seconds and give it a little gas once started. It then idles rough for 5 seconds or so. I had the codes read with a cheap code reader and nothing was found. Any ideas????

I would do a fuel pressure test.

Measure:
Cold fuel pressure (ignition on - engine off)
Cold cranking fuel pressure
Engine full warm pressure
Pressure after engine off
Pressure should hold after engine off so watch it for 5 minutes or so.

Post back what you find.

//2000CAYukon

If yours is anything like my problem was, it runs fine once started but just getting it to start was a problem, especially after already being driven for the day. Initially I thought it was the basics; plugs, wires, possibly plugged fuel filter. As it turned out, after noticing similar posts, it definitely had the symptoms of the Fuel pressure regulator. I went to a local parts store and it was $70, and about a 15 minute procedure to replace it. And that appears to have done the trick, it fires right up first try everytime now, just like it used to. Mine is a 2000 Z71, 5.3. The regulator is located on the driver's side fuel rail right on top of the intake, it's even easy to get at. I would definitely give this a try, it worked on mine. Good Luck!

As it turned out, after noticing similar posts, it definitely had the symptoms of the Fuel pressure regulator. I went to a local parts store and it was $70, and about a 15 minute procedure to replace it. And that appears to have done the trick, it fires right up first try everytime now, just like it used to. Mine is a 2000 Z71, 5.3. The regulator is located on the driver's side fuel rail right on top of the intake, it's even easy to get at. I would definitely give this a try, it worked on mine. Good Luck!

I had the same problem and same solution fixed it. However, I would not go aftermarket on the Fuel Regulator. I but a aftermarket regular on there and I got 10 mpg from 19mpg. I replaced it with one from the dealer and I went back up to my normal mpg.