Help. idles fine drives bad low power

[pitbull419]

Hi, ok heres the run down. My 1998 ranger xlt 4.0 is running weird. It idles a little high(around 1000rpm) but smoothly. When i rev it up it "pops" usually around 2000rpm. Now when i try to drive its a different story it pops a lot and seems to be lacking power. After running a KOEO scan the only code i recieved was p0453(evaporative emission system pressure sensor/switch high input) Then i ran a KOER scan and recieved the above code and the following p1151( lack of h02s21 switches sensor indicates lean) , p1137(lack of h02s12 switches sensor indicates lean). Currently the truck has no exhaust past the downpipe(what the first cat bolts to)problem existed before exhaust was removed(i thought cats were plugged thats why i removed) it has all new plugs, wires and coil pack. Firing order is correct ive checked it a hundred times. Also there is a faint odor of gas under the hood but i cant find anyleaks even vaccume. Any info, ideas and suggestions are greatlyappreciated. Thanks

 

[Earl43P]

Lean codes on a 4.0 make me think vacuum leak, which is often caused by bad intake manifold seals, upper and lower. I highly doubt that both upstream O2 sensors failed the same way, at the same time.

http://www.therangerstation.com/Magazine/January2011/gaskets.shtml

Welcome to The Ranger Station!

 

[cp2295]

Yeah if you smell the gas when it's cold only it could definitely be an intake leak which would be leaking combustion fumes out.. Do a fuel pressure check, could even be the fuel pump getting weak

 

[pitbull419]

Ok i have checked and checked again for vacuum leakes especially the intake mani. I did check my fuel pressure and it is right around 65 where it is supposed to be.