Hi there. I am having a weird problem with my 89 XJ6. It hesitates after stops and sometimes when stepping on the throttle to pass on the freeway. Once up to speed however it purrs along with no issue. It only seems to happen with quick acceleration or with stop and accelerate. I have been checking things piece by piece, testing as per the manual but I cannot figure out exactly what is going on. I thought it might be water in the fuel tank at first but now am not convinced as I have run it down and refilled it twice now and the problem is not getting better and seems to be getting worse. Should I be changing out the fuel filter, 02 sensor? Any suggestions definitely appreciated as I am at a total loss here. Pretty much everything is checking out fine when I test voltages as per the manual. Don't see any cracked hoses or wires anywhere. In fact I have traced down every wire pretty much and have checked all of the hoses.

WD

 

WD,
If there are no codes, you could certainly tidy up the normal things to see if there is any improvement. If it's due, I would certainly do the fuel filter as that is relatively cheap. It might also be time for a good throttle body cleaning. O2 sensor should throw a CEL, so I wouldn't mess with that. I guess in other words, perhaps a good old fashioned tune up is in order. It could very well be something unseen with plugs and wire.

Good luck!
Scott

 

Still having the same issue after the fuel filter change. The plugs and wires are brand new, new oil change, new coolant, etc, etc. Really unsure of what else could be causing the issue.

 

Did you check your throttle position sensor? Coolant temperature sensor? MAF clean? Throttle body clean?

Sounds like my problem and I have narrowed it down to the TPS. Make sure it's closed, open, and referance voltages are in range. Then make sure it has smooth voltage transition from closed to open and open to closed. Easily check this while you are pulling the throttle body to clean it.

For example my tps reads ~.52 volts when closed and ~4.8 when open with a 5v referance. All in range, but where my problem happens is at about 2.5 to 3.5 volts it will jump around so say hit 3v then jump down to 2.8 and then back up to 3.2 etc.

From my understanding this confuses the ECU and causes it to run the engine fuel/air mixtures kind of funky. For me throwing a lean/rich code at the O2 sensor.

 

So far everything has checked out fine with the exception of the part identified. It appears as though there is a connector under this connector and no sensor in place. I cleaned everything and checked the voltages and resistance values on all of the sensors as indicated and things looked good. Cleaned the Throttle Body very well and reconnected. During reconnective I noticed the connector I circled was not connected to anything and there was nothing there to connect it to but it appears as something should be there. Anybody know what is supposed to be there? I believe that is more than likely the issue.





WD

 

Anybody know what is supposed to be plugged in there? I have 2 plugs and no sensor.