P0101 + P0300 = ?

[Fless]

A leaky injector or a bad fuel pressure regulator could cause the quick bleedoff of fuel pressure. How long does it take to drop to 44 when you turn the key off?

 

[tlynch]

A leaky injector or a bad fuel pressure regulator could cause the quick bleedoff of fuel pressure. How long does it take to drop to 44 when you turn the key off?

It dropped faster than it took me to walk from the driver's door to the engine compartment.

I looked at the fuel pressure regulator while I was checking injector resistance. It looked relatively new. At least it looked cleaner than everything around it. It may have been replaced at some point.

 

[tlynch]

I am tentatively declaring victory.

Over the last couple of weeks, my Tahoe has taken longer cranking to start, and would run rough for a couple of seconds before hitting its stride. Combined with the fuel pressure data, this definitely seemed to confirm fuel delivery issues.

Yesterday, I replaced the fuel pressure regulator, fuel pressure regulator vacuum line and fuel filter. Right after I was done, the truck started immediately. No hesitation. It sat for 32 hours, then started immediately again. Very nice change.

I wasn't smart enough to hang onto the borrowed fuel pressure gauge to measure the difference, but the experience is much improved.

Thanks again to everyone who shared their time and knowledge helping me.