2003 gt - sputtering/missing

[ndean52]

I just put a fuel pump and fuuel filter on the car yd bc the mechanic told me the machine said it was losing fuel pressure. I had another mechanic check the coil packs ber i had the pump put on bc i hear thts a regular problem with my year of mustang. Coil packs are fine and my car is still sputtering after the pump and filter. It didnt help at all. My car is not stock, and about 8 months ago i put an off road h pipe on the car. I have got the MIL eliminators for the 02's yet either, maybe thats the problem?? help please lol

[Ralph123]

Does your check engine light come on?

[Blue)(Fusion]

Since he has deleted the cats and does not have MIL deletes plugged into the rear O2s harnesses, he will have the MIL illuminated.

ndean, I found it a little hard following your description. Might help in the future to use proper spelling and not the internet shorthand. But anyway, with the new pump and filter, does the fuel pressure stay within spec now or did you not check yet? If it's not within spec, try replacing the Fuel Pressure Regulator.

If the fuel pressure is within spec after the new pump and filter, then check the air intake. Get some CRC MAF Cleaner and clean your MAF sensor and remove the ground cable from your battery for atleast 15 minutes to reset the computer.

What is not stock on your car, besides the offroad H-pipe? And get your codes read. There may be another reason that your MIL is lit other than the cat delete.

[ndean52]

Yes my light stays on & i have .410 gears, jlt ram air intake, accufab 75mm throttle body and plenum with a steeda spacer, hypertech thermostat, long tube headers, and a sct chip with 4 tunes

thanks for the replies, and i would think the mechanic would check and make sure the pressure was ok after he installed the pump, but who knows.

I forgot to mentuion i ran the codes at Advance Auto when the car first started all this. Ran the numbers 1131 & 1151 - both said fuel/air metering. I have also put some fuel injector cleaner and cleaned my air filter. I will grab some cleaner to clean the MAF now.

Do you recomend anything else or did i not explain something well enough?

[Blue)(Fusion]

P1131 & P1151 =Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1 & No. 2.

Codes mean there's alot more air than expected causing the lean condition. If the MAF is dirty, it will read less airflow than actual and will cause lean condition. If cleaning it doesn't help, then recheck the fuel pressure at the rail.

Oh also, you are running the factory MAF with that ram air intake, right? Also is your HO2 sensors located in proper locations with those long tubes? If they're not located in a good spot, they will not send proper A/F ratio to the PCM.