2008 GMC Sierra 1500,have no manual,have display telling me low tire pressure and no mileage;how do I get my mileage display back?

replace the tpm sensor in the wheel, or somtimes it can be repaired at the tire shop

That is really low mileage for issues but clunking into gear is a symptom of a bad universal joint on your drive shaft. Does it clunk in D and R?

Sounds like an oil pressure problem. The clacking sound is most likely the lifters are collapsing due to loss of oil pressure. You may have a failing oil pump.

have it tested using a manual gage if still low then main baring ore most likely bad that would mean a over hall if is really low and bearings bad should be making rattle noise when started up first few seconds

have your front end components checked, and have a front end alignment performed, double check your tire pressure.

for better freeway mileage a low back pressure exhaust will help, also run tires at max pressure, this is around 45 PSI, in town there is little you can do.

sounds like a vaccum leak between you intake and your EGR

Let me understand this.. I ask you guy's a question and before you send me the answer, you want to charge me. Then you ask if I resolved the problem and if so, tell you how I did it. Well I did resolve it and I would be more than happy to tell you how. $29.95 with get my detailed response.

You can follow this to reset it.
Ignition ON, initiate the TPM Learn Mode
using one of the following procedures:

1. On vehicles equipped with keyless entry, simultaneously press the keyless entry transmitters lock and unlock buttons until a double horn chirp sounds indicating the Learn Mode has been enabled. The left front turn signal will also be illuminated.
   
2. On vehicles not equipped with keyless entry, press and release the driver information center (DIC) INFO button until the TIRE LEARN message appears on the DIC display. Press and hold the SET/RESET button until a double horn chirp sounds indicating the Learn Mode has been enabled. The left front turn signal will also be illuminated.
3. Increase/decrease the tire pressure for 8-10 seconds then wait for a horn chirp. The horn chirp may occur before or up to 30 seconds after the 8-10 second pressure increase/decrease time period has been reached. Once the horn chirp has sounded, the sensor information is learned and the turn signal in the next location to be learned will illuminate.
   After the horn chirp has sounded and the right front turn signal is illuminated, repeat step 2 for the remaining 3 sensors in the following order:
   3.1. Right front
   
   3.2. Right rear
   
   3.3. Left rear
   
   When the left rear sensor has been learned and a double horn chirp has sounded, the learn process is complete and the RCDLR exits the learn mode.
   Ignition OFF, adjust all tires to the recommended pressures

im in cold quebec there preset i install snow tire with rim on those with regular valve light stay on because people dont whant to spsnd and extra $160.00 for those valve in cold zone tire pressure are low be ready to reset that computer many time this winter pierre