98 Cobra with BADDDD hesitation...

[ree11]

I have a 98 cobra with almost 72K miles and it has developed a very bad hesitation and shake. It hesitates in pretty much all conditions but sometimes it runs perfect. Only under about 70% throttle or higher is there no hesitation. It also has a bad shake at idle. The check engine light comes on intermittently and says it is running lean and rich in the #1 bank. I checked and replaced the spark plugs and a tiny amount of oil was on that one. I am thinking it is maybe a valve cover gasket leak?? Any help is appreciated.

Thanks,

ree11

 

[stang dreamer]

i have a 98 cobra as well, just about covered 75,000 miles and only recently had the exact same problem. to stop the engine light i just checked the 02 sensors and replaced the bank 2 sensor. no more engine light and the idle is miles better. maybe worth checking your 02 sensors.

 

[Lil'_Red_Rocket]

Have you changed the plugs and wires? If they are 10 years old you may have a spark issue and it could cuse the shake at idle and the hesitation.

 

[ree11]

I replaced the plugs but not the wires, but they look like they have been changed recently. They are very clean. I am installing the Steeda adjustable clutch cable tomorrow, so I will replace the O2 sensors while I am under there, and if that doesn't fix the problem I will go to the wires and check the plugs again for oil and maybe go to the valve cover gaskets from there. If that doesn't fix it then I guess to the fuel system. But I hope we dont have to go that far lol!

 

[fiveofanatic]

Rich and lean doesn't make sense. What code # is it?

 

[ree11]

EXACTLY!!! Not sure the code # but there were 2 codes, one said it was rich, and the other said it was lean

 

[fiveofanatic]

Get the codes, dude, gotta have the codes.

 

[98'CobraSVT]

Check your MAF sensor as well