Finally I put the two together. I forgot about the FPR problem I had. After days of tuning and fuel trims everywhere I started to think I was doing something wrong. Finally got my VE with in 5% in open loop when I go back to close loop and enable Maf my trims end up high teens %. So I start Maf tuning copy paste %, fuel trims are 0 to -4% idle still at -10 to -12 a little fat so I scan log copy paste problem cells.By this point Im the man, Then I notice everytime my ac compressor comes on rpms dip and afr richens. Then look at my fuel pressure which is vacuum reference and its at 55-57 psi with 20 hg vac and at idle. Idle normal is about 50 psi. So FPR is sticking. Causing all my tuning problems...I think or a least hope!

 

replaced FPR now fuel pressure showing higher numbers...

 

What kind of problems were you having before you replaced the reg.? i have been having some serious misfire problems where the afr spikes lean and it runs so bad its like its only running on a couple of cylinders. i just changed the fuel pump and it didn't help at all. Sound familiar? i was thinking about changing the reg but the fuel level sending unit was shot anyway so i did the pump first.

 

No misfire's here. Just when tuning everything was going in right direction, then some other days everything was off again so I would retune wich would correct it but then it would go back and be of again. My fuel pressure would vary I guess one day higher than others and would throw everything off.