I'm just the driver, so I will be relaying all suggestions to my mechanic .... My jeep can run perfect one trip to work / one entire day and then be mildly to horribly rough running the next day.
On the trips/days it is destined to act up, it starts out running just fine. I sometimes think there is some correlation between driving higher speeds on rough highway as to when it starts to act up.
The rough running is most often between 50-65 mph, but not limited to that range. These last couple of days lower speeds have been an issue too. If I can take my foot off the gas and coast, it almost always goes back to running perfect, altho since it has started acting up at lower speeds, it can idle a bit rough too. Also if I can give it a whole lot more gas and drive a lot faster, it usually runs much less rough. When it's acting up, it has less power (hills / take offs / corners), and gas mileage drops to a depressing 10.5 mg. Now if I have to really put my foot into the gas pedal to get it up to speed, it may shift harder and spew black smoke. It will then go faster and then seconds later have an extra burst of speed without any additional pressure on the gas pedal. Oh, and sometimes the CE light is on (always says an O2 sensor which we replaced) and other times it is not, regardless of how it is running.
Over the time we've spent trying to resolve these issues, it has slowly gotten worse and the problems more pronounced. Here is what's been done:
I added a bottle of Heet, Water remover and injector cleaner to a full tank of gas which seemed to work.
When the problem returned on the next full tank of gas, I added another. Did not help this time.
new O2 sensor
replaced coil pack
replaced injectors
checked for vacuum leaks
replaced a ground wire
checked connections
unplug / re-plug the computer (may or may not make any difference)
This weekend's game plan is to go thru all the wiring with a fine tooth comb. Any suggestions will be greatly appreciated
On the trips/days it is destined to act up, it starts out running just fine. I sometimes think there is some correlation between driving higher speeds on rough highway as to when it starts to act up.
The rough running is most often between 50-65 mph, but not limited to that range. These last couple of days lower speeds have been an issue too. If I can take my foot off the gas and coast, it almost always goes back to running perfect, altho since it has started acting up at lower speeds, it can idle a bit rough too. Also if I can give it a whole lot more gas and drive a lot faster, it usually runs much less rough. When it's acting up, it has less power (hills / take offs / corners), and gas mileage drops to a depressing 10.5 mg. Now if I have to really put my foot into the gas pedal to get it up to speed, it may shift harder and spew black smoke. It will then go faster and then seconds later have an extra burst of speed without any additional pressure on the gas pedal. Oh, and sometimes the CE light is on (always says an O2 sensor which we replaced) and other times it is not, regardless of how it is running.
Over the time we've spent trying to resolve these issues, it has slowly gotten worse and the problems more pronounced. Here is what's been done:
I added a bottle of Heet, Water remover and injector cleaner to a full tank of gas which seemed to work.
When the problem returned on the next full tank of gas, I added another. Did not help this time.
new O2 sensor
replaced coil pack
replaced injectors
checked for vacuum leaks
replaced a ground wire
checked connections
unplug / re-plug the computer (may or may not make any difference)
This weekend's game plan is to go thru all the wiring with a fine tooth comb. Any suggestions will be greatly appreciated
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