I lost power yesterday twice; it happens very quickly and comes back just as smoothly. There is no jumping or jerking. I turned a corner at slow speed and was headed up a hill. All at once I feel the car start to slow. I looked at the gauges and saw no lights but the tach drop ever so slightly. Within a couple of seconds everything was back to normal. It did it again on the freeway on the way home. I have had a slow starting problem when the engine is cold due to low fuel pressure I believe. Either from a bad check valve, pressure regulator or Sam’s broken fuel line connection at the fuel pump.

I searched under loss of power, transmission and surging to no avail. Please let me know if you had this problem and the fix. The car runs quiet and smooth with a 107,000 miles on it. It's just keeping me on my toes.

 

Well the Jag acted up on its next outing. Problems started while still inthe garage. I started it but it died right after firing. I slowly restarted bywaiting for it to go through the system check before cranking the engine, thisseems to help. Later that evening while coming home it started but in the ABS/TRCLimp Mode. Again I fixed it by starting it slowly. I put in a new DieHard(AGM-49) battery that night and left it on a charge. Next morning while tryingto drive it, it died at an intersection, when I quickly restarted it went intoABS/TRC limp mode, restarting slowly fix it for the drive home.

Since no one has any help ideas, I'll use this thread to track the fix forthose who might run into this in the future.

 

Please post the MY and model (XK8 or XKR). Also I recommend first that you check for codes and report back here with the actual codes if there are any.

 

I would check the voltage while the car is running, maybe it's a dying alternator?

I wouldn't think that a fuel problem would cause the ABS/TRC fault, but might not hurt to verify the fuel pressure with an external gauge.

 

I would not rule out fuel pump(s). The warning codes don't necessarily relate to the problem. When I start my car, if I turn too sharply to the left, my ABS/Traction control warning light comes on (I believe bad contact due to stretching of the wiring harness). Yesterday, after starting the car after sitting for 5 hours at the golf course, I pulled out of my parking spot and, as usual, warning lights came on, but this time was followed by Transmission temperature warning. Obviously, the tranny was not hot as it had sat for 5 hours. I restarted and all warnings cleared. The electronic warnings on these cars are sometimes nutty. Your problem would seem to be fuel related.

 

Thanks for the replies.

It's a 2001 XKR Coupe, like the one in my picture. It has 107,000 miles onit.


One other thing that was worth noting, when I started it in the garage and it died right after firing I notice a warning "Not Charging" or something like that coming up on the info screen. I thought of coarse not the engines not running, but maybe that was a real warning about the charging system as it died.

I checked the codes and only had P1111.

Before I put the new battery in, I took it to O'Riley to have the battery and alternator checked. The kid seemed to be having some trouble with the handle held meter. First it said the alt was bad, then he ran it again and it said it was OK....then it said the battery was OK but was 3/4 through its life. Lots of beeping going on….

Then he checked the new battery I had just bought at Sears and his meter said it was OK.

So at best the test was inconclusive.

 

Sounds like it could be the throttle body. Try cleaning it and the air inlet and breather hoses.

while your there also clean the tps sensor connection.

 

Shop say I need a new thorttle body ,part C2A 1445. $2100
Anyone have good luck use a rebuilt one from ASI?
I need to make choice soon, let me know what you think.

 

I would first clean the Throttle Body and clean the connections to the Throttle Position Sensor, the Pedal Position Sensor, and the Throttle Motor.

 

I appreciate the suggestion but it's in the shop, which is no small task getting it there and it needed the coolant reservoir replaced too, so I just ordereda rebuilt TB from AIS.

Should have all the parts here by next Tuesday. I'll let you know how itworks out.

 

I picked up the Jag from the repair shop,

ASE rebuilt TB $512
Coolant Reservoir Tank $178
Labor $423

Engine light came on 5 miles from the shop.

My next thing to do is read the Engine Code
Disconnect and ground the battery terminal to clear the ECU so it relearns itself.


Any other ideas?

Thanks!

 

I got a P0171, P0174 & P0105
I call the service guy and asked if they had cleared the ECU by disconnecting the battery and grounding the positive for 5 min as the instruction said to do, Nope! So I did that.


Now I'm getting a MIL and just a P0105 (MAP/BARO Circuit Malfunction).


Car runs fine so I put some black tap over the MIL until I can take it in for further diagnosis.

 

Something else that was weird that happened just after picking up the car, the LED's that show the miles or MPG on the speedometer would dim for a while then come back. It didn't do this again after I hard reset the ECU. Never seen that before?

 

Mine usually dim when the automatic headlights come on. 01' XKR convert.
I was having those same faults, but with a P1642 code after I got everything wet trying to wash mud out from under the car. After a couple days of drying out with the battery disconnected, it started acting normal. But the faults returned after driving less than a city block. I knew I had messed up. Didn't know what to do, but I had to get home. It wouldn't go 5 mph, so I floored it to see what that would do. It took off even with all the fail safe on, but wouild not shift to 3rd gear. I stopped and turned it off for maybe 30 seconds. Upon restart everything came back to normal and is now running just fine. I thought we had gotten rid of the Lucas gremlins.

 

All is fixed now. The shop called and said the hose had fallen off the MAP sensor. It was like glued on when they removed it and didn't fit tight when then put it back on. Since Super Chargers create pressure in the manifold, not just vacuum, it blew it off.

I looked over the weekend for the MAP sensor but thought, that can't be it because it doesn't have a hose to it.