Back in January I had to do a engine swap (4.6) and at the time the best replacement I could find was from a 2003. It worked flawlessly but at the time I noticed I was getting about 50 kms less per tank than the old engine. I had put the cap on my truck at the same time so I blamed it on the extra drag. But now that the summer is here and the cap is off I am down to 475 kms per tank compared to 575 with the old motor. Has anyone else done a PI into NON-PI swap without doing anything to the computer and found the same thing? I e-mailed VMP and he said to check the injectors and the MAF sensor but they seem fine. Any advice?

 

Think a tune would solve your problem if everything else is ok. Get Justin to set you up.