My 2003 Chevy Silverado is running rough?

2003 Silverado P0171 & P0174 OBD II Codes TSB 3232?

• Tough question, I know....But, I have a 2003 Chevy silverado and the check engine light has been coming on for about 4 weeks. I ran a scan which resulted in P0171 and P0174 OBD II Codes. These indicate that fuel rails (or banks) are running lean on both sides. A internet search revealed that TSB 3232 acknowledes this problem but my mechanic can find no record of TSB 3232 for my vehicle through All Data. I've ordered a replacement fuel filter, but am pessimistic since I've already replace the fuel filter about 20k miles ago. How do I find the source of this illusive TSB 3232? http://www.carcomplaints.com/Chevrolet/Silverado/2003/tsbs.shtml http://www-odi.nhtsa.dot.gov/cars/problems/tsb/tsbsummary.cfm?tsbs_id=10011692&prod_id=103253&model_yr=2003&make=CHEVROLET&model=SILVERADO&type=VEHICLE

• Answer:

  TSB-GENIII Cold Engine Misfire at Idle with P0171 and/or P0174-I didn't have any trouble finding it. BUT are you experiencing a cold rough idle that goes away as the engine warms up? & Randome misfires at an idle? If not, then this Bulletin will probably not help you. If you are then: 1. Check for leaking intake manifold seals around the intake ports. If they are leaking, replace them with updated part#89017589. The new ones are teal green & the old ones are orange. 2. Check the intake plenum for warpage. If it is warped, then you will need to replace it, too.. Another thing to look for if you have a P0300 DTC, too: 1. Perform a fuel injector balance test on all 8 cylinders. 2. Inspect Oxygen sensors for corrosion or water intrusion. 3. Check for excessive exhaust backpressure. Some other things to check for: 1. Inspect the Secondary Air Injection System for proper operation. 2. If the fuel pressure is too low, then it will set these DTC's. 3. Check Vacuum hoses for defects, splits, & proper connections. 4. The system will go lean if an injector is not supplying enough fuel. The lean condition is most likely present during high fuel demand.