99 Sierra 1500 4x4 Will Not Complete Readiness

frankstl · March 2, 2011

Hi, I have a 99 ext cab sierra half ton 4x4 with the z71 package with the 5.3L and it had 2 trouble codes in computer along with the service engine soon light, codes 171 and 174, lean condition on both banks, well considering id had the truck at that point for a little over 3 years now and put about 85k or so miles I decided id tune it up, new air filter and plugs, just did the fuel filter a couple months ago along with the fuel pump. Within 15-20 minutes of installing the new plugs and firing up the engine the light went off and it stayed off the rest of the day when driving the vehicle.

The next morning the light was still off and I cleared the previously stored codes and tried to reinspect the vehicle, at which point it was showing the evaporative, heated o2, and catalyst as not completed on the readiness test, was told I needed to drive the truck more and give the system time to complete the drive cycle, well now its been 5 days and roughly 600 miles of driving and 2 more attempts at passing the readiness and still the same condition as first try, and still no engine light which wont till the system completes the reset of all monitors I assume.

Have read of similar issues on other vehicles but not my exact type of truck and wanted to know if anyone knew of this issue and if so what corrected the problem as I would like to get my inspection sometime before the thirty days is up, preferable sooner as the hassle of being pulled over all the time and explaining this over and over will get old really fast.

Thanks for reading this and any help or info that can be offered.

frankstl · March 2, 2011

Hi, I have a 99 ext cab sierra half ton 4x4 with the z71 package with the 5.3L and it had 2 trouble codes in computer along with the service engine soon light, codes 171 and 174, lean condition on both banks, well considering id had the truck at that point for a little over 3 years now and put about 85k or so miles I decided id tune it up, new air filter and plugs, just did the fuel filter a couple months ago along with the fuel pump. Within 15-20 minutes of installing the new plugs and firing up the engine the light went off and it stayed off the rest of the day when driving the vehicle.

The next morning the light was still off and I cleared the previously stored codes and tried to reinspect the vehicle after driving it for a few hours and about 100 miles, both highway and city driving, at which point it was showing the evaporative, heated o2, and catalyst as not completed on the readiness test, was told I needed to drive the truck more and give the system time to complete the drive cycle, well now its been 5 days and roughly 600 miles of driving and 2 more attempts at passing the readiness and still the same condition as first try, and still no engine light which wont till the system completes the reset of all monitors I assume.

Have read of similar issues on other vehicles but not my exact type of truck and wanted to know if anyone knew of this issue and if so what corrected the problem as I would like to get my inspection sometime before the thirty days is up, preferable sooner as the hassle of being pulled over all the time and explaining this over and over will get old really fast.

Thanks for reading this and any help or info that can be offered.