Tahoe issues

[SAWYER]

I picked this up from a guy I know for 2000, it runs and drives good but the miles are high(250k) It doesnt leak or smoke and is in good shape, 4x4 is also a nice plus. Something is wrong with the gas meter, it frequently will show low fuel but if I move hard side to side it will show the actual fuel level. It also is rough idling when the engine is cold and is fine after it warms up. I hooked up a bluetooth code reader and used Toruque Pro to get the error codes.

 

[jlee]

http://www.tahoeyukonforum.com/threads/p0171-and-p0174-codes.36727/

A few likely culprits are listed there.

 

[SAWYER]

thanks

 

[herm0016]

(i cant see the pics)

I would pull the tank and replace the pump and sending unit for the gas gauge issue, also, check the connections.

rough idle: clean the MAF and replace and seal the knock sensors that are under the intake. the knock sensors are a known issue.

i would probably change the plugs and wires if they are original as well.

 

[JulesMaximus]

Lean condition could be caused by clogged fuel injectors couldn't it?

 

[BStorm]

Other than the failing knock sensor, the remaining codes are pointing to deferred maintenance items.
A lean code on both banks point to a fuel quantity problem. I would replace the fuel filter first. It if doesn't resolve, test fuel pressure (and quantity) at the rail before going further.
Low fuel volume would definitely contribute to the P0300 code as well (too little fuel to fire at times). Replacing the plugs and wires would definitely be recommended as their age is likely undetermined (probably original).

My dad's '05 Silverado with the 4.3 V6 ran to 191,000 on original plugs (I insisted on replacing them for him), so its possible it still has them.

 

[jlee]

Other than the failing knock sensor, the remaining codes are pointing to deferred maintenance items.
A lean code on both banks point to a fuel quantity problem. I would replace the fuel filter first. It if doesn't resolve, test fuel pressure (and quantity) at the rail before going further.
Low fuel volume would definitely contribute to the P0300 code as well (too little fuel to fire at times). Replacing the plugs and wires would definitely be recommended as their age is likely undetermined (probably original).

My dad's '05 Silverado with the 4.3 V6 ran to 191,000 on original plugs (I insisted on replacing them for him), so its possible it still has them.

It could also be a failing/dirty MAF sensor and/or leaky intake manifold gasket.

 

[BStorm]

It could also be a failing/dirty MAF sensor and/or leaky intake manifold gasket.

I agree its a definite possibility, though I would still recommend the deferred maintenance items done first. Having a tuned up ignition system and a verified fuel quantity/pressure will make troubleshooting possible intake issues easier.

I had to do the same thing on my 04' Venture to find the culprit. 120,000 miles and no previous owner records. Code P0131 (low voltage oxygen sensor). Plugs, wires, fuel filter, air filter replaced. No change. O2 sensor was reading fine under low/medium load (used a scan tool). Fuel Pressure tested good under idle and load. Fuel quantity was good. Turned out the MAF sensor was vastly under reporting air flow under heavy load and the computer couldn't compensate enough. It was only exposed because the previous troubleshooting steps eliminated the other candidates. No MAF code was ever set.