Kuplex
Software Developer
Hopefully someone can give me a few ideas on what to check here. I've got a 08 GT manual.
Basically, over the last couple weeks, when holding speed I get a light bucking/hesitation feeling. It's almost like you're lightly letting off the pedal and tapping it. It's not major but feels like a random pulse. The RPMs do not change at all that I can see.
This may be related or not, but I was trying to see if a noise was engine related or tire so I let off the gas and threw the car into neutral at around 60mph, the rpms dropped, fluctuated a little from 300-500, then dropped to zero, and then the engine died. I don't remember it ever doing that before but it's been a long time since I've done something like that. Putting it back into gear jumped the engine back to life just like starting a car without a working clutch. This was about a week ago.
Anyway, I have changed the throttle body (which did help with overall smoothness), fuel filter, air filter, coil boots, spark plugs (all looked fine), and looked all over for any kind of vacuum leaks. No coolant leaks. No knocking. No engine sputtering (other than the light throttle pulsing). No weird smells or sounds that I have noticed.
I decided to datalog a short drive today and see if I could catch anything. Sure enough it started pulsing again when holding speed around the 2m mark (sorry forgot to time it). On the second datalog, around the 3m 52s mark, I gave it about half throttle up to 60mph, let off the gas, threw it in neutral and the engine died. Maybe that's expected behavior though?
My fuel pressure and duty cycles seem to be fine, although I'm not an expert at reading these data logs. Any advice? Thanks.
Cliff
Basically, over the last couple weeks, when holding speed I get a light bucking/hesitation feeling. It's almost like you're lightly letting off the pedal and tapping it. It's not major but feels like a random pulse. The RPMs do not change at all that I can see.
This may be related or not, but I was trying to see if a noise was engine related or tire so I let off the gas and threw the car into neutral at around 60mph, the rpms dropped, fluctuated a little from 300-500, then dropped to zero, and then the engine died. I don't remember it ever doing that before but it's been a long time since I've done something like that. Putting it back into gear jumped the engine back to life just like starting a car without a working clutch. This was about a week ago.
Anyway, I have changed the throttle body (which did help with overall smoothness), fuel filter, air filter, coil boots, spark plugs (all looked fine), and looked all over for any kind of vacuum leaks. No coolant leaks. No knocking. No engine sputtering (other than the light throttle pulsing). No weird smells or sounds that I have noticed.
I decided to datalog a short drive today and see if I could catch anything. Sure enough it started pulsing again when holding speed around the 2m mark (sorry forgot to time it). On the second datalog, around the 3m 52s mark, I gave it about half throttle up to 60mph, let off the gas, threw it in neutral and the engine died. Maybe that's expected behavior though?
My fuel pressure and duty cycles seem to be fine, although I'm not an expert at reading these data logs. Any advice? Thanks.
Cliff
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