I have a 2000 RCSB with a 5.3. The truck has 116,000 miles and usually runs well. Two days ago the truck began to feel sluggish on take off, but only just after start up. About a mile down the road, the truck will run fine. The SES light then came on, I scanned it, and it said code PO33, I think, but it said Knock Sensor low current or low voltage, something along those lines. I am wondering what this could possibly be. I cleared the code, drove the truck 25 miles and it came back. You can definately tell it is pulling timing when cold though. Any help is appreciated.

 

the search feature kicks a$$...but since your new I'll help ya anyways. You probaly pulled a p0332 knock sensor code for the rear knock sensor. What happens usually is that the knock sensor get corroded from water intrusion under the intake. To fix it your going to have to remove the intake and I'd replace BOTH knock sensors, then you build a "dam" around the knock sensor hole to keep water from getting in there again.

 

Thanks for the advice. So is this a fairly common problem? Also, what if I just ignore it and continue to drive it, will it compound the situation. Thanks in advance.

 

Very common problem actually...ignore and drive? you'll see more of the same , lack of performance, loss of MPG, the PCM will just go into a "limp" mode and wont allow for any timing changes other than base values. DIY and save some money if your mechanicly inclined to do so, the intake gaskets will cost more than the sensors themselves. Shop labor will run about 3 hours worth, IIRC so avg shop charges 225$ for labor and about 150$ for parts for one sensor/gaskets or close to 200$ for both sensors/gaskets.

 

Nice! you are dead nuts on with that diagnosis.

 

haha.... thanks 5 yrs in a GM dealer as a driveability tech will do that for ya

 

Thanks, I appreciate the advice. I will probably end up doing it as soon as a get a chance.