95cobragirl

hey guys maybe you can help me out with this problem im having....the cobra is acting up...cant pinpoint the problem....when you step on the gas the car hesitates...then if you are just driving the throttle opens up the rpms kick straight up and then fall and then she starts sputtering like shes not getting gas or shes not getting air...when i come to a stop or if im slowing down and push in the clutch she dies...now ive ran the moa fuel treatment through her and stuff like that....i have an obd1 reader and twice the check engine light has come on and it spits out a 511 code which in my repair manual it says read only memory failure replace PCM....im not entirely convinced i need to replace the computer....it seems to me like the fuel system is malfunctioning or i have a sensor with the fuel injection system that is going out...but it doesnt throw a code...ive replaced the tps, egr, and the mass air sensors in the past...could this be an O2 sensor problem...a speed sensor problem...im not sure...all of the symptoms in my book say it has something to do with the fuel system...which i agree...now i know that the PCM plays a big part in controlling all of this....but the car doesnt act up all the time....it only does it everyonce in a while....im confused...im thinking maybe fuel pump is going...or the mass air sensor is out again....i dont know...please help so i dont have to take it to the ford dealership and get ripped off....luv jenna

mustang12

Have you pulled out the sparkplugs to see if they all look good. My stang was acting real funny as well, and when I pulled the plugs I noticed that all 4 plugs on the passenger side where running rich. Change the 02 sensor on the passenger side on the exhaust and that fixed the problem.

Hulk

Probably not the fuel pump. They don't tend to give up while the car's running. Check the fuel pressure. Are all the connections tight on all the sensors you replaced? Do you smell gas or anything when this happens? Does the temp gauge read hotter? Check the connections at the PCM. As msutang12 said, read your spark plugs also. Normally any bad sensor will throw a code, but this sounds like a bad connection or an intermittent ground problem that causes the computer to do weird things. I hate the intermittent ones... Good luck.

PS. Could also be a blocked exhaust (cat) too, but I would think the problem would be constant. How does it sound when this is happening?

P.S.I.cho

any trouble lights? it could be a number of things, fuel, spark, vaccume, MAF, TFI