Sorry about the incoming wall of text:
So when I first bought my car in December it would occasionally buck/misfire when on the throttle getting on the freeway or going up a hill, etc. Now it's progressed to about every day when I drive it there's at least one stutter, one bucking event, etc., and it's also been stalling at idle. It also has the occasional long start, taking about 5-6 seconds to fire while stumbling to life.
Last weekend I was about to head north to school (about 80 miles) and when I pulled out of my parents driveway it immediately started bucking every time I hit about 2000 RPM. I had to turn around at the end of the block and pull right back in their driveway. Here is a video while in neutral, foot steady on the throttle: https://www.youtube.com/watch?v=YVg0sM1wjQg. You can't see in the video, but every time it happened the CEL would blink on and then shut off. After shutting it down the check engine light came on and the stomp test proved itself useless by just flashing constantly and not displaying any codes. I checked the spark plug wires and pulled them off/put them on several times to make sure there was connection, and then the problem repeated itself only at 4000 RPM instead.
The next morning my dad and I checked the throttle position sensor and the crankshaft position sensor, both seemed to be within spec as per the TPS Pelican Technical Article and the Bentley manual. I ended up replacing the fuel pump relay just to see if that would have any effect. Car started and drove normal, no problems all the way back to my house 80 miles north.
Last week it has been bucking/stuttering at idle quite often, about once per day. Long starts are still happening. It will often stumble when idling and the check engine light will come on for a few seconds, then go out. It falls suddenly to about 400 RPM then jumps to like 1300, then falls back to a normalish idle.
Yesterday I replaced the throttle position sensor only to find the one I'd gotten was faulty, so I put my old one back on (seemed to be working fine) and discovered that my friend and I had created a vacuum leak in the process. We also unplugged/replugged every sensor multiple times to make sure that electrical contact was being established and there wasn't any corrosion on the terminals. It started and drove home fine though, but it hated quick throttle input and idled high due to the vacuum leak.
I need some input. Could it be the AFM? ECU? The ECU has a chip but I have no clue what kind. I have access to both a working spare ECU and even a MAF conversion if I so chose to try that.
I'm running out of ideas. Oh and I forgot to mention that it also runs rich. Has been since I bought it.
So when I first bought my car in December it would occasionally buck/misfire when on the throttle getting on the freeway or going up a hill, etc. Now it's progressed to about every day when I drive it there's at least one stutter, one bucking event, etc., and it's also been stalling at idle. It also has the occasional long start, taking about 5-6 seconds to fire while stumbling to life.
Last weekend I was about to head north to school (about 80 miles) and when I pulled out of my parents driveway it immediately started bucking every time I hit about 2000 RPM. I had to turn around at the end of the block and pull right back in their driveway. Here is a video while in neutral, foot steady on the throttle: https://www.youtube.com/watch?v=YVg0sM1wjQg. You can't see in the video, but every time it happened the CEL would blink on and then shut off. After shutting it down the check engine light came on and the stomp test proved itself useless by just flashing constantly and not displaying any codes. I checked the spark plug wires and pulled them off/put them on several times to make sure there was connection, and then the problem repeated itself only at 4000 RPM instead.
The next morning my dad and I checked the throttle position sensor and the crankshaft position sensor, both seemed to be within spec as per the TPS Pelican Technical Article and the Bentley manual. I ended up replacing the fuel pump relay just to see if that would have any effect. Car started and drove normal, no problems all the way back to my house 80 miles north.
Last week it has been bucking/stuttering at idle quite often, about once per day. Long starts are still happening. It will often stumble when idling and the check engine light will come on for a few seconds, then go out. It falls suddenly to about 400 RPM then jumps to like 1300, then falls back to a normalish idle.
Yesterday I replaced the throttle position sensor only to find the one I'd gotten was faulty, so I put my old one back on (seemed to be working fine) and discovered that my friend and I had created a vacuum leak in the process. We also unplugged/replugged every sensor multiple times to make sure that electrical contact was being established and there wasn't any corrosion on the terminals. It started and drove home fine though, but it hated quick throttle input and idled high due to the vacuum leak.
I need some input. Could it be the AFM? ECU? The ECU has a chip but I have no clue what kind. I have access to both a working spare ECU and even a MAF conversion if I so chose to try that.
I'm running out of ideas. Oh and I forgot to mention that it also runs rich. Has been since I bought it.
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