Ok folks this is my first of probably many tech posts. I apologize if these questions have been asked/answered before but Im at work and mytime online is limited.My problems are as follows:

1. Faulty fuel reading. Very annoying! About a week after I bought it I was at a light with a load of friends and it just shuts off. Luckily we were half a block from a gas station but jeez this is a pain. The gauge works when the truck is in gear and it has between 3/4 to a full tank but if it goes below it doesnt read the needle just goes crazy.

2. Start-up rattle. On a cold start-up when the motor turns on you can hear a rattling that sounds like valve-clatter but its only audible for maybe3 or 4 seconds. Oil level is fine and you only hear it in the morning. Not a big deal for me as long as its something normal for this engine. Oh, its got about 79,000mi

3. Wierd idle. At times the motor idles a little rough which gets me nervous.

Any help is appreciated!!!

 

#1 - Fuel level sender unit - Crappy part is you have to drop the tank to replace it.

#2 - Not usually normal... Sound like you may have a sludge build up problem that may allow the lifters to leak down over night. What weight oil are you using? What brand oil? What brand oil filter?

#3 - When was the last time you did a tune-up (plugs, wires, cap & rotor)? Also, you may want to pull off the throttlebody and give it a thorough cleaning. The IAC valve is located on the side of the TB. You'll want to pull it off and give the bore and pintle (tip on the valve itself) a good cleaning to remove any built up carbon. Be careful not to move the pintle location.

You may also want to look into cleaning the EGR valve and MAF sensor. Both of which are detailed in other posts. I don't have the time at the moment to find them for you, but someone else may be able to link to them.

Good luck and let us know on the questions I presented above.

 

EGR Cleaning

 

The rattle could also be piston slap. GM has TSB's about this condition, and mine does it also. GM states no problems will occur from this noise.