Milford Cubicle II
NAXJA Forum User
- Location
- Out there.
2000 4.0 AW4
So last night I was driving along and noticed what at the time I thought felt like my tranny slipping. So I dove into the gas to investigate and felt what turned out to be a very harsh misfire. While accelerating, the engine had a tremendous misfire and eventually just shut off just like I had turned the ignition off. Upon attempting to restart it, the engine wouldn't even act like it was going to start. So out of desperation, I disconnected my battery, then reconnected it then it started up and idled fine. So I took off down the road and it would run like a top but as soon as I got to about 30% open throttle it would start missing badly again, and eventually die then I'd have to go through the whole disconnecting of the battery thing again to get it running. Except this time the idle was pretty rough too and it was no longer so smooth below 30% throttle. I decided to just get home before I stranded myself then I dove into it today some more and now it pretty much just runs like crap all the time but is still significantly better below 30% throttle.
What really freaked me out was as I was just idling listening and watching the gauges, my speedo jumped up to 100mph then back down to 0! Then just a couple seconds later it did it again except it went to about 55mph.
Then that made me realize, lately I've noticed a couple times when I've turned off my ignition with my headlights still on and opened my door and it's not beeped at me like it normally does. And the beeper is in the instrument panel so that makes me thing maybe there's a loose connection in there somewhere. Now I could care less about the stupid beeper but it made me wonder if my ECM was f'd. But I'm pretty sure that beeper is just a mechanical AND circuit but the speedo, that's controlled by the ECM iirc. Btw, I held down my odometer button while turning on the ignition to put it through what is apparently supposedly some kind of test and apparently it passed cause all the gauges danced for me I dunno, just thought I'd throw that out there.
It's not RPM dependent at all, I can go easy on the pedal and bring the tach up to 5k smoothly all the way. In fact, if anything it even seems more load dependent than TPS dependent because I can squash the gas in neutral and peg the tach... roughly albeit but I can do it without it dying. However, if I tried that in even first gear there's a good chance it would just shut off like it did.
I've unplugged every sensor and injector individually to see if they make any difference whatsoever and the only one that even kinda makes a difference is the MAP.
Also, almost every engine management sensor is less than 2 years old including the MAP, TPS, CPS, CMP, IAC, and both O2's. Also, I checked the TPS for linearity and dead spots with both my scan gauge and an analog DVOM and it's good. The MAP readings on the scan gauge show that it's working fine too.
Sorry for the huge post but I really try to figure things out or at least dig as deep as I can before I have to bother anyone else about it. I'm baffled, can anyone give any insight?
So last night I was driving along and noticed what at the time I thought felt like my tranny slipping. So I dove into the gas to investigate and felt what turned out to be a very harsh misfire. While accelerating, the engine had a tremendous misfire and eventually just shut off just like I had turned the ignition off. Upon attempting to restart it, the engine wouldn't even act like it was going to start. So out of desperation, I disconnected my battery, then reconnected it then it started up and idled fine. So I took off down the road and it would run like a top but as soon as I got to about 30% open throttle it would start missing badly again, and eventually die then I'd have to go through the whole disconnecting of the battery thing again to get it running. Except this time the idle was pretty rough too and it was no longer so smooth below 30% throttle. I decided to just get home before I stranded myself then I dove into it today some more and now it pretty much just runs like crap all the time but is still significantly better below 30% throttle.
What really freaked me out was as I was just idling listening and watching the gauges, my speedo jumped up to 100mph then back down to 0! Then just a couple seconds later it did it again except it went to about 55mph.
Then that made me realize, lately I've noticed a couple times when I've turned off my ignition with my headlights still on and opened my door and it's not beeped at me like it normally does. And the beeper is in the instrument panel so that makes me thing maybe there's a loose connection in there somewhere. Now I could care less about the stupid beeper but it made me wonder if my ECM was f'd. But I'm pretty sure that beeper is just a mechanical AND circuit but the speedo, that's controlled by the ECM iirc. Btw, I held down my odometer button while turning on the ignition to put it through what is apparently supposedly some kind of test and apparently it passed cause all the gauges danced for me I dunno, just thought I'd throw that out there.
It's not RPM dependent at all, I can go easy on the pedal and bring the tach up to 5k smoothly all the way. In fact, if anything it even seems more load dependent than TPS dependent because I can squash the gas in neutral and peg the tach... roughly albeit but I can do it without it dying. However, if I tried that in even first gear there's a good chance it would just shut off like it did.
I've unplugged every sensor and injector individually to see if they make any difference whatsoever and the only one that even kinda makes a difference is the MAP.
Also, almost every engine management sensor is less than 2 years old including the MAP, TPS, CPS, CMP, IAC, and both O2's. Also, I checked the TPS for linearity and dead spots with both my scan gauge and an analog DVOM and it's good. The MAP readings on the scan gauge show that it's working fine too.
Sorry for the huge post but I really try to figure things out or at least dig as deep as I can before I have to bother anyone else about it. I'm baffled, can anyone give any insight?
arty:. 
