Help understand these symptoms please!
 

Hi,

My buddy has a 2000 1500 with the 5.3 gas engine in it. He's been experiencing rough idle/stalling when it's cold. He's also a couple of times gotten code P0171 (System too lean - bank 1).

I hooked it up to my AutoEnginuity yesterday after the truck was all warmed up. The short term fuel trim for bank 1 was between -1 and 1, while the short term fuel trim for bank 2 was about 145. Also, the Average Injector PWMs were way out balance on bank one vs. two.

So the scan tool seems to be saying that bank TWO has injector problems, and it's continually trying to richen that side. The DTC, though, said that bank ONE was too lean.

I logged the O2 sensor voltages, but I didn't have time to delve deeply into what was happening with them.

Any ideas?

Thanks,

B

Re: Help understand these symptoms please!
 

Have you changed your intake manifold gasket yet?
These motors were infamous for poor gaskets resulting in the codes and symptoms you described.

Re: Help understand these symptoms please!
 

99+ trucks are notorious for the injectors getting clogged. we have a fuel injector cleaning tool, that runs 75 psi of pressure instead of the normal 55-60. it usually fixes the problem your having

Re: Help understand these symptoms please!
 

I've got the same symptoms without throwing a code. I suspect intake gaskets. I'll be checking with the b12 in the next day or two. I bet it's a vacuum leak between intake and head. Only in the cold is my main clue. Time will tell. dkf

Re: Help understand these symptoms please!
 

Give an update when you can to see if changing the intake gaskets fix your problem. I'm on the short road to changing mine in the next week or two. So it would be nice to know what results you get.