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04 mustang gt help! FORD!?
Ok.... I have a 2004 mustang gt, bought like this; 70mm throttle body, stock is 65mm? and has a bigger MAF unknown size. and the cats are cut off piped with 4 o2 sensors. everything else seems stock engine wise. THE COMPUTER IS STOCK FROM FACTORY as far as i know. never tuned just bolted parts on it id say.
You tell me how you think this car runs...... tach goes up and down maybe 200 300 rpm or so at idle, has a little sputter at idle kinda like a miss or left over fuel or something. and engine dont idle smooth it shakes just a little more than normal. really dont think it has miss tho.
so adding them parts and del the cats and no pc tune would i get these results? just dont seem to have the power it should but never drove another stang like it.
no no no i bought this car the way i explained... the bigger maf, throttle body cut off cats, was like that when i bought it. i heard when u cut cats off it runs rich..... well with it getting more air from bigger maf and tb..
thats the whole reason im asking so i can get car to run hard like it should.... explain what happens when you cut cats...... explain what happens when car gets more air than it suppose to bein bigger maf and tb.
thanks for any help. i totally understand adding these parts makes it run shitty but not to bad really just minor glitches, the power cuts out about 4k on tac. will set you in seat then suddnly lets up a little and engine still runs smooth
3 Answers
- ?Lv 69 years agoFavorite Answer
If you have a bigger throttle body and MAF on the car and the computer doesn't know about it (or is tuned for it), then you will have problems. The MAF tube is a known size that is used in the airflow calculations.
Also, deleting cats removes back pressure, but it can also negate exhaust scavenging if the factory header is tuned for it. Most people don't realize running without cats can actually lower horsepower in some cases. Also, with the stock PCM you will always have a check engine light with P0420 and P0430 all the time.
So if you want your car to run right, you either have to restore everything back to stock (especially the MAF) or else pay the money and get a custom dyno tune. In its current state, you might end up damaging the engine from running too lean.
- 9 years ago
Maybe IAC valve or MAF isn't working correctly. Are the spark plugs foiled? If so could be a fuel problem. If you have the money just start replacing sensors. Thats what I use to do until I got sick of spending money. Hey they all need to be replaced eventually.
- Anonymous9 years ago
You did mods, and as I can read, you did the mods the wrong way, so yes, your unprofessional mods can cause that, specially when you mess with sensors.
If you want to learn to tune your car, you can use a car performance simulator, there you can virtually do the mods instead of damage your car, then only do mods that provide performance increase, try at http://www.nxgtrsim.com/
