01 Silverado problem

[Jsdirt]

Lean code with a misfire doesn't jive with raw fuel smell out the exhaust. 

 

With your scan tool hooked up, go for a full throttle run in 1st gear into second (where safe to do so, obviously) - watch your o2s - both upstreams should be pegged rich (800mv or higher). If they're not full rich at full throttle, you have a fuel delivery issue (clogged injectors, fuel filter, bad new fuel pump or a defect in the wiring (power or ground), OR you've got a bad MAF.  MAF grams per second at idle rule of thumb is roughly the displacement of the engine in liters - I.E. a 5.3L should read close to 5.3 g/s, and so on. Might want to set the scan tool up to graph the MAF, and note any large spikes or dropouts in the signal. If you see that, you've found a bad MAF.

 

One other variable in all of this could be clogged catalytic converters. Usually the vehicle will start and run (sometimes), but fall flat on its face when any kind of load is applied (same symptom with a fuel delivery problem).

[Jeffhaynes]

Which 2 are the upstream. My scanner is showing bank 1 sensor 1 getting 800mv and bank 1 sensor 2 only getting to about 400. Then other 2 are 700-800

[Jsdirt]

Upstream means before the catalytic converter(s) (cat(s) ). If they're just sitting there, and not switching, you've got a problem either with the sensors or fuel delivery, or unmetered air.

[Jeffhaynes]

I haven't found any air leaks and I've did all tricks over a few times. Here are my fuel trims at idle. And mass air flow rate was

.7 lb.min at idle 

St bank 1- .8%

Lt bank1- 25%

St bank 2- .8

Lt bank 2 -.8%

At 2000 rpm

St -8 to 3.1 

Lt 25%

St -4.7

Lt 2.3 

[Jsdirt]

Focus on that bank 1 o2 sensor - I suspect it might be stuck rich if in fact there are no air or vacuum leaks. The negative short term at 2k suggests there IS a vacuum leak.

 

Pinch off the brake booster vacuum hose, and check the trims again. If ST goes way negative right away, you've got a bad brake booster, or a leak in that hose downstream from where you pinched it off.