[ndfrspd]

I've made numerous posts on here about how my car idle is all fucked, but what ive failed to mention is that when my foot is steady on the pedal or when its not on the pedal at all and the car is cruising, the engine will bogg and the car will jerk by itself. I know for sure my injectors are clean, and the mechanic who checked out my car did say the fuel pump was weak......... can that send fuel surges to the engine? or is that the fuel sending unit? PS: im going to replace the fuel filter anyways cause it so cheap and i have a new fuel pump in the mail.

[Asdrubael]

Does sound to me your car is in fuel need. Either the fuel-pump or fuel-sending unit are shot. Perhaps your fuel-filter is dirty (this could also apply to your fuel-lines). But by my guess you're defenitely looking in the right direction. It could also be a defective air-mass meter, causing your CPU to give faulthy values to the amount of air coming into your engine, thereby giving to little fuel to the mix. I've had it happen to me on my Cougar.

[Randy Stinchcomb]

Originally Posted by Asdrubael Does sound to me your car is in fuel need. Either the fuel-pump or fuel-sending unit are shot. Perhaps your fuel-filter is dirty (this could also apply to your fuel-lines). But by my guess you're defenitely looking in the right direction. It could also be a defective air-mass meter, causing your CPU to give faulthy values to the amount of air coming into your engine, thereby giving to little fuel to the mix. I've had it happen to me on my Cougar.

good answer but it could also be from bad or weak O2's how many miles on the car and have the O2's ever been replaced? usually by 80k, there all used-up.....

[ndfrspd]

Ive never replaced the O2 sensors and it does have offroad h pipes without cats... i turned the back two sensors off with MILs. Is there a fuel regulator unit or is that the same as the sending unit?

[Randy Stinchcomb]

Originally Posted by ndfrspd Ive never replaced the O2 sensors and it does have offroad h pipes without cats... i turned the back two sensors off with MILs. Is there a fuel regulator unit or is that the same as the sending unit?

1998 Mustang, which is a bit of a bastard year on the fuel system, has a fuel pump and fuel level sender thats all in one unit...there is a Fuel Pressure Regulator on the fuel rail but it's a fixxed piece and Not serviceable....the rear sensors are actually O2 monitors and just measure the cats efficiency and have no affect on making adjustments in fuel trim, only the Oxygen Sensors can-do that, those are the ones up infront....

[ndfrspd]

Originally Posted by Randy Stinchcomb 1998 Mustang, which is a bit of a bastard year on the fuel system, has a fuel pump and fuel level sender thats all in one unit...there is a Fuel Pressure Regulator on the fuel rail but it's a fixxed piece and Not serviceable....the rear sensors are actually O2 monitors and just measure the cats efficiency and have no affect on making adjustments in fuel trim, only the Oxygen Sensors can-do that, those are the ones up infront....

you sir, are some kind of genius. ive had 123214 people reply to me that just say "oh you might want to try this or you might want to try this instead... blah blah blah." Now having learned what you just posted, I know exactly the problem in my car. THANK YOU!

[Randy Stinchcomb]

Originally Posted by ndfrspd you sir, are some kind of genius. ive had 123214 people reply to me that just say "oh you might want to try this or you might want to try this instead... blah blah blah." Now having learned what you just posted, I know exactly the problem in my car. THANK YOU!

no problem, hope you get the solved and Im far from being a genius just alot of experience wth Racing Ford products, EFI systems and cars in general