I started the car today and it idles fine . When i drive it once it goes past 3000 rpm it starts to sputter. Any ideas ? When its just sitting there idleling its fine but when i drive it and it goes above 3000 rpms it sputters.

 

Small backfire sounds or does the car actually hesitate badly?

 

the car naturally back fires but it starts to hesitate pretty good after 3K

 

pull the codes first. Then check the TPS and fuel filters.

 

even with out a check engine light on i can pull codes?
How many fuel filters does the Fc have ? its my first fuel injected turbo project

 

yea you can still pull codes. There is the fuel filter in tank with the fuel pump and one in the engine bay on the driverside below the oil filter.

 

Def. check codes... sounds like limp mode to me.

 

He has a 10th ae with mechanical omp so I dont think it's limp mode. The only thing remotely close to limp mode on s4 is if the water thermo sensor (one behind the waterpump housing) is malfunctioning/not working correctly.

 

My mistake... I see no mention of 10th AE in his posts. .

 

Yes i have a 10th AE. I just changed the water pump about a week ago could that water thermo sensor have gone bad too? Can i acces the fuel pump filter with out having to drop the tank? Why would that water thermo sensor going bad cause the car to hesitate like that? Like i said im new to the fuel injection turbo rotory so all this info is greatly appreciated.

 

jm85rx7 if you want i can pass by your house and help you if need be just pm me... but to get to the fuel filter in the gas tank just life the rear carpet youll see a metal covering on the left hand side with 4 screws holding it down unscrew that and under that youll have the fuel pump screwed down with about 8 screw unscrew all that and fuel pump comes out with filter and the other fuel filter is on the drivers side subframe... and if you replace the waterpump check the green connection in front of the alternator a little down if its off or shaken while driving car will go into limp mode.
TwEaK

 

Yes i have a 10th AE. I just changed the water pump about a week ago could that water thermo sensor have gone bad too? Can i acces the fuel pump filter with out having to drop the tank? Why would that water thermo sensor going bad cause the car to hesitate like that? Like i said im new to the fuel injection turbo rotory so all this info is greatly appreciated.

 

I dont think I've heard of a water thermo sensor going bad. Probably the wiring. I think it was a green rectangular plug that is fastened with one of those U shaped wire clips. If the clip wasnt put on securely it could have fallen off.

Yes you can access the low pressure filter (on the fuel pump in the tank) without dropping it. Just go to the hatch area and lift up the carpet and youll see a metal plate on the left side take that off and then take off the oval shaped tank lid and pull it out. Careful not to strip those phillips head screws they are sometimes rusted on.

The water thermo sensor sends signals to the ECU (or maybe the other way around) I always forget so it's a safety precaution.

 

first of all i would like to thank all of you who replied to this post. i tried everything you guys suggested. New plugs , new wires, used thermal sensor, made sure the green plug was good, and both fuel filters, to no luck the car was still hesitating. So in to the shop it went and it was a combination of two things. First the fuel pressure regulator took a dump so a new aeromotive FPR was put in. Second the car has a third gen fuel pump and they have this little preasure cap on top that releases preasure and from what i was told they go bad sometimes so i bought another third gen fuel pump and you can take that cap of and seal it with a sealer. Everything was put back in and the car runs like a champ. So hope this might be of help to someone else with a similar problem. And like i said before good looking out to all you guys that replied and didnt make me go try to do a search tha will take forever.

 

More people should follow up on their threads with solutions.