The best i remember when i last tuned my maf With the stock injectors i had good fuel trims. Now using 42lb green top ford injectors which I believe are 45 on my rail. I hafta set them to 39lb to have acceptable long term fuel trims and it's still around a positive 10 ltft. Any ideas? Should I use the 42\45? And maf tune? the fuel trims won't be able to compensate. i kinda thought this part would be easy.