I posted this in a couple other forums. I guess I'll post it here for a wider audience:
Ever since I did a PI intake/Cams swap, the power is good but my gas mileage has been down by a good amount. If I drive all freeway I can get around 20 mpg. All city I'll get around 15 mpg.I recently checked my mpg and with a 70% highway and 30% city I averaged 16.2 mpg driving conservatively. I've been hunting this problem down for a while and here are all the things that I have done/changed:
I've tried different tunes from Bama (same bad mpg, went back to stock)
Compression check: All near 180 psi +/- 5
Re checked timing (Pulled cover off and re-timed)
Checked fuel filler grommet for leaks
Checked for binding brakes
Checked vacuum at all locations I could think of (-21 in/hg)
Checked for vacuum leaks spraying carb cleaner from intake to bottom of intake manifold
Checked for exhaust leaks
Checked for clogged cats (using vacuum gauge and by infrared temp gun)
New Egr/Egr Solenoid
Checked vacuum pressure from solenoid to EGR
Checked EGR passage way by applying vacuum to EGR (engine stumbles and dies)
Checked voltage at DPFE
New Fuel pressure regulator
Fuel pump is only a couple years old (ford oem unit) along with the fuel filler grommet
Checked fuel pressure (40 psi with vacuum line off the regulator)
New Engine gaskets (valve cover, timing cover, etc)
New Oxygen senors (2 upstream only)
New 19lbs injectors with new o-rings and pintles
New Vacuum Lines
New Fuel filter
New plugs
New wires
New coil packs
New Iac
New PCV
New ACT temp sensor
New TPS
Datalogging with my SF3:
No DTC codes
LTFT for both sides are +/- 5% (although bank 1 is usually always higher by 4-5% than bank2)
STFT both banks +/- 2%
ECT within spec
ACT within spec
IAC duty cycle at idle is 40% and goes up to 98% at WOT
MAF ad counts is at 160 at idle and goes up to 810 at WOT
Spark timing at idle seems to be around 13 degrees
TPS seems to be in spec
LOAD at idle is around 15% at idle and goes up to 86% at WOT
My mods are on my profile page under the information tab.
I've logged misfires for each cylinder and I'll randomly (sometimes not) get only 1 or 2 misses on cylinders 4,5,6,7,8 (not enough to set a code) if i'm idling for a long time. But let's say I drive on the freeway for hundreds of miles, I will not get one misfire.
At this point, I'm a little lost as to what to do. I've thought that this might be normal mpg but seeing that other forum members get a lot better mileage with more mods than me, I think my car could be doing better. Perhaps I'm leaking fuel in a location that is not so apparent (I don't smell fuel anywhere) because if it was something related to a tune up wouldn't my fuel trims be off? Any leads are appreciated. Thanks