p0171,p0174

CHEVROLET SILVERADO
Avatar
MACK2448
  • MEMBER
  • 2 POSTS
I have a 2002 Chevrolet Silverado with the 5.3 engine. It has 106,000 miles. Last winter my service engine soon light was displaying 0171 and 0174. Fuel pressure was in specs. I replaced MAF, IAT, air filter and could find no vacuum leaks. Problem still there. I replaced fuel filter twice. No good. On cold mornings the truck would idle rough for 8-10 minutes then smooth out. No one could tell me anything else so I resorted to driving it and resetting the SES light every few days. After the weather warmed up in spring I have had no light all Summer. It has been 30 degrees for 2 days now and my light is back on with 0171 and 0174 showing. Fuel pressure tested right and I bought the MAF cleaner recommended by my parts store clerk but nothing changed. The truck runs fine after it warms up. Any help is appreciated. THANKS
Oct 31, 2007 at 10:56 AM
Advertisement
Avatar
SERVICE WRITER
  • ✓Experienced Mechanic
  • 9,123 POSTS
The 5.3 had a problem with leaking fuel pressure regulators is one thought, typically you would smell some raw fuel.

A leaking intake is the next thing I would question, spray some carb cleaner around the intake and look for a change in the rpm. This has to be done when it is cold as the contraction of the metals are at their greatest.
Oct 31, 2007 at 11:28 AM
Avatar
MACK2448
  • MEMBER
  • 2 POSTS
I traded pressure regulators with a friend, mine would still trigger codes, his still hasn't. I sprayed starting fluid around the entire engine compartment with no change but I don't think the engine was cold. I will try that next. Thanks for the help, Mack
Oct 31, 2007 at 2:12 PM
Avatar
SERVICE WRITER
  • ✓Experienced Mechanic
  • 9,123 POSTS
'd be careful using starting fluid, that's pretty volitile.

Start with going around the intake and plenum gaskets first that is the most common place on these that I have seen.

Troubleshooting is knid of funny, if the problem isn't there, you can really spin your wheels. The COLD gives away the secret on this one.
Oct 31, 2007 at 10:30 PM
Avatar
DENNYP
  • ✓Experienced Mechanic
  • 1,824 POSTS
[quote:1580170a38="Service Writer"]'d be careful using starting fluid, that's pretty volitile.

Start with going around the intake and plenum gaskets first that is the most common place on these that I have seen.

Troubleshooting is knid of funny, if the problem isn't there, you can really spin your wheels. The COLD gives away the secret on this one.[/quote:1580170a38]THE P0171 & P0174 CODES ARE A LEAN FUEL MIX CONCERN.THIS WOULD BE CAUSED FROM THE INTAKE GASKETS LEAKING WHEN THE ENGINE IS COLD.
Nov 2, 2007 at 12:01 PM
🔧 Tools & Auto Repair Parts
Find automotive tools, diagnostic equipment, and replacement parts for your next repair.
Shop on Amazon →
Paid affiliate link. As an Amazon Associate, we earn from qualifying purchases.
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Ask a new question

Frequently Asked Problems for This Vehicle