Error Code 0171 And Wet Plug?

[tomo62]

Hi, wondering if you can help me, GMC Yukon with the Vortec V8 Engine (it's a friends - so details are sketchy...)

 

It was missing, code reader said #1 plug wasn't working. Replace Plugs, and #8 was a bitch! Also replace air-filter.

 

After running low on fuel and re-filling, car starts running really poorly. Certainly missing on one or more cylinders.

 

Fill tank with 91 and injector cleaner. Not much difference.

 

Recheck all plugs are firing, coil leads, clean MAP sensor and Throttle Body with CRC cleaner. Running Better.

 

Code reader says error 0171: lean on Bank 1.

 

Checking spark Plugs are OK, I have pulled the plug from Cyl 1, twice and both times the plug has been wet with fuel, and the vehicle has been sitting for hours.

 

Replace the injector - and how much do they cost?

 

Need an accurate diagnosis, money isn't an object - it's the object at the moment!

 

Thanks