Hey guys,
I haven't posted here in a few years but I know there are a ton of smart people around so I'm hoping someone has some tips here. My son's new to him '05 Silverado 5.3 4WD 4L60E truck is stalling when placed in reverse or drive. It doesn't happen every time. Sometimes it can sit there for 15 seconds without moving and then it suddenly dies. Details below:
176K miles
Shifts kind of hard into 1st
No codes
Cleaned TB and MAF
Replaced knock sensors (had a code for one) and replaced front driver O2 probe (had a code plus all 4 driver's side plugs were black)
New plugs and wires
Changed trans fluid and filter and put in a new TCC solenoid (no change)
Hooked up external fuel pressure gauge and watched it stall a couple times in the garage shifting gears. Fuel pressure was around 60 psi and didn't drop right before or after it died.
Idle definitely drops a little bit going from P to D or R (maybe 600 in P and then drops to 500-ish in gear)

I'm at a loss on what to try next. Torque converter or trans issue or is this something else causing it to stall??

 

Need to hook up a scanner and monitor if gear positions are changing. (Ex. Park and then changes to reverse when placed in reverse.) It sounds as if the PCM is not seeing the gear and still thinks it is in Park/Netural and not raising the rpms.

 

Thanks. The trans is definitely changing gears but the rpms are staying depressed when it does. I will say that last night I cleaned the MAF for a second time (son did it the first time) and the rpms were a little higher in gear while parked. It would take a momentary tiny dip when you shift into D or R but then recover to the same idle speed as before. This is making me think its got to be MAF or TB related. It also didn't stall during that short test drive. I'll test it out again tonight to see what it does. Unfortunately I came out yesterday morning to find a large pool of new trans fluid under the pan. I have no idea why but that new gasket is leaking and I know for a fact I put it on right and torqued all those pan bolts to spec. Frustrating!

 

iac stuck maybe and not allowing it to adjust in the TB maybe?
it happened to me once and didnt evan throw a code.

 

That's what I wondered too but this is a drive by wire TB for '05 so there is no IAC "motor" like in the cable TBs.

 

You use HP Tuners? Look at table (ECM) 12610

Closed throttle " Idle Spark Advance" in DRIVE, the 0 and 400 RPM column(s) on the LEFT:
Fill in 30 Degrees for the top 7 rows from airmass= .08 down to .32

You've just built in 'Stall Saver'
Give that a try, report back.

 

Lock up clutch issue?

 

I'll try and look tonight. I have the software just haven't licensed this truck yet.

 

One question on this - I licensed the truck and will make the changes tomorrow. If I'm only adjusting 0 and 400rpm columns, and it starts to dip below 550-ish rpm again (I believe warm/hot idle is around there), then it won't kick up the timing until it drops to 400 rpm right? I drove it some more tonight and it didn't die while driving but it seems the main issue is when I let off the gas and coast/brake to a stop. When the rpm drops under 1000 it will sometimes dip down to 500 then right back up to 600-700 until I get to a stop and then will sit at the right idle speed. That was until I got home and tried to shift from park to reverse when it was hot. Idle dipped again and stalled.

 

Updated the table to 30 degrees and no change. I also replaced the MAF with a new one and no change. At this point it seems to drive ok but the idle dips almost every time when coasting to a stop and the rpms drop to about 400 then immediately pop back up to 550-ish. The only other thing I could potentially try is a new TB although I don't want to keep throwing parts at it.