Gas cap off car works fine... and ideas to get me going?

[MajEK]

Title really says it all... The car runs fine when I take the gas cap off but on tight after warm up and WOT the car has a lack of power like struggling going up a hill and getting the rpms up. Downshifting helps a little but it seems like its holding back.

Its a 94 CX with a d15b I put in myself with a USDM intake manifold and a p28 with jumper disabled to run stock.

Anyone had this problem? charcoal canister? injectors? idk

 

[XpL0d3r]

Check o2 sensors.. I had a similar problem (minus the gas cap issue, never tried taking it off though) where my car would run fine cold, but as soon as it warned up I had NO power at all until about 3500 RPM's... I mean NO power. I could have it floored around 3k in 2nd gear and people were walking past me..

 

[MajEK]

Thanks for the reply. After getting the engine in I had to replace my cat since I drove it with the timing off and fried it gutless. With the o2 before the cat, makes sense it would be probably worse off. No codes though and just yesterday it passed smog on stock p28 .


It'll be my next thing for sure just wanted to see if it might be something else. I guess I'll find out.

 

[MajEK]

Gutted 2" Magnaflow bolt on cat (testpipe) for sale btw! <~~ I'll make a FS thread soon.

 

[glaze26]

you try a new gas cap , they do go bad.