1999mustang2000

i need help quick. Before we get into that i just wanted to say hey long time no see =) i have'nt been around in a while and my mustang is still down, hoping it'll be back up this week! But on another note;

I have a check engine light on and my car is acting wierd it has a loss of power and lags going into WOT and sometimes doesn't go into WOT, i had the light checked but forgot exactly what is was, the guy said it had sometimething to do with the air to fuel not mixing properly. The car has a brand new TPS and MAF and i just installed a new CAI and Exhaust.

Car is 04 Impala SS 3.8 Supercharged

teej281

Clogged or bad injector(s), bad o2 sensor, clogged fuel filter. Other than that I have no idea. If you have the ability to, datalog it as it might be a fuel pump on the way out.

1999mustang2000

The code is P0420

I do not have a cat but i do still have all my oxygen sensors installed. But it also says that sensor doesnt affect the engines performance.

945LSTANG

what car are you talking about OP?

a_penquin

Sounds like weak spark up top or a very rich condition at/around WOT. Im stumped as far as causes on a fuel injected vehicle. You normally see this on over carburated vehicles.

1999mustang2000

its a 04 impala ss

im sorry i forgot to put that

btw the plugs and wires are also brand new.

When you floor it, it kicks down and won't go WOT

at this point im thinking a very clogged fuel filter or the fuel pumps going out, car has 130,xxx and i dont think the fuel filters been changed. Ima seafoam it tommorrow and see if that helps any, its pissing cats and dogs here so i cant change the fuel filter.

a_penquin

I'll go for the fuel filter, check your pressure.....

1999mustang2000

that sounds like a good idea i never even thought about checking the pressure, what should it be at?

a_penquin

That you'll have to hit the books for. Every vehicle is somewhat different. It should be somewhere between 40-60psi I think.

1999mustang2000

ok ill let y'all kno the results lol