Lean miss/lack of power at WOT - It appears many people have had to following issues: Cold stumble/miss especially after a cold restart. Also experiencing lack of power at wide ...

It appears many people have had to following issues: Cold stumble/miss especially after a cold restart. Also experiencing lack of power at wide open throttle.

New plugs, wires, air and fuel filter. The MAF has been cleaned. Snapshot taken with scan tool at WOT with no apparent problems. Noticed that the fuel mode stayed in closed loop at WOT. Not sure, but I thought the mode should go to open at WOT.

Does anybody have any suggestions?

Oh yeah, its a 99 silverado, 4.8 L with a manual transmission.

What kind of plugs did you put in? Was this happening before you did the tune-up? How did you clean the MAF?

Hav you checked your tps

I installed OEM Plugs after experiencing the problems. They appeared to help but not fix the problem. I cleaned the MAF with power off electrical contact cleaner and clean compressed air. The TPS perameters are indicating normal on the scan tool.

Update since my first post: The lack of power at WOT has gone away. Accerates good now and has good fuel economy. It still has the cold temperature jerky issue. I have learned to live with that since it is a rare occurance now.

At this time, I have to conclude that the MAF cleaning along with the computer relearning was the main solution. Could be wrong but its running good for the time being.

I also think that raising the fuel pressure 3 to 5 psi at WOT would help. Not exactly sure how I will do this, but gonna try something. Maybe come up with a second pump for a push pull system with regulator. Some time with a tuner would be a better choice.

Check your fuel pressure, maybe it's getting a little weak.