Car sometimes lacks power on downshift and stumbles!!

[crazycooter]

Yesterday i was cruisin my car around and when i downshifted from 4th to 3rd my car lacked power. I then shifted to second same problem. When i shifted to first the car responded normally and continued to to so for the time being. Is this a fuel problem and if so where should i look first?

 

[regulator213]

put some seafoam in your gas tank first just to make sure your fuel system is cleaned out. What size injectors do you have? are you tuning at all? stock fuel pump?

 

[crazycooter]

Everything should be bone stock except the clutch, flywheel, exhaust (2.5 in. turbo-back vrs complete exhaust w/ test pipe), and k&n air filter. Is seafoam available @ autopart stores? I also have a venom 400 performance chip that i usually don't use but it is spliced into the air sensor and tps. The problem is similar to what experienced with my honda accord i had a few years ago. It had a "sticky" valve that finally colapsed