Ive already cleaned the throttle body and MAF sensors, I'm getting a diagnostic code for the Oxygen sensor before the cat that reads high voltage bank 2 sensor 1 P0152, would this cause a high idle..?

 

Yes, it absolutely could be the culprit. I would recommend changing all four of your oxygen sensors at this time, however, being that they run about $80 a piece, you may want to delay that.

I would at the very least, replace the faulty oxygen sensor.

I would strongly consider changing BOTH of the the upstream sensors. The downstream ones aren't as critical. If you're willing to climb under the car and work in cramped conditions, they can usually be changed pretty easily.

NTK 25018 or Bosch 13789 is what you want. (please doublecheck me)
I have bought both over the years and have found that both are stamped NTK..including the OEM Denso products that are significantly more expensive.

Be careful with any antiseize you apply to the threads, if you are too liberal and some comes in contact with the head, you'll be replacing it. You definitely want to use some, just don't go crazy with it.

By the way, just because you've cleaned the MAF doesn't mean it isn't malfunctioning. Since you happen to have a Trouble Code, let's resolve that first though.

 

Well, Im afraid your wrong, changing out the O2 sensors did nothing for the High Idle. Im probably going to have the ECM reprogrammed to get rid of it. I took a diagnostic scan and there are NO DTC's detected.

 

That always seems to be the cure for the high idle on these engines. I've thrown enough parts on my past two cars to have learned that now.

At least you resolved your code issue. I'm sure a mechanic would have charged you about $250 to do it.

 

This post of yours still intrigues me.

I go back to the other post I made suggesting that it could be your temp sensor. One way to check this out is when you have the high idle situation, you can short the sensor which would trick the car into thinking that the coolant is at operating temperature.

What you're describing is that you cold start the car, and it idles fine. I'm assuming you can drive the car and everything is fine until you shut it off and then do a hot restart? Am I properly describing the issue?

If that's the case, the coolant sensor may be sticking cold, or something, that would tell the car to increase the idle to get the car warmed up.

 

https://www.jaguarforums.com/forum/x.../#&gid=1&pid=1

You want to pull the plug out of #17 on the engine key above and run a wire from one plug socket to the other. (The coolant sensor itself can run unplugged, don't worry about it, youre shorting the plug that attaches on to this sensor, not the male leads on the sensor itself.)

It's worth a shot.

 

Vee, where is the coolant sensor located..would'nt it throw a code if its not operating right..?

 

It would not throw a code. If you open the link in my previous post, you'll notice a picture of the engine with a key identifying components. You want #18.

 

Man, thanks thats a god picture to look up every once in a while, for other things too. Appreciate it.

 

It still has a High Idle after warming up and shutting off the engine then starting it back up immediately, goes to about 1300 to 1500 rpm.,,after I replaced the Temperature sender...?

 

Dammit, I screwed you. I meant the Sensor, #17, not the sender. The sender just sends the signal to the dash. The sensor is what tells the ECU how to adjust for hot/cold engine.

 

Well I replaced the sensor and the High Idle is still there after warming up the engine.

 

And again, just to clarify, the idle is fine when the engine is cold.

What happens after startup, the car relies on a preprogrammed set of values to run the engine, until the oxygen sensors warm up, thenn it relies on actual data from three devices to idle:
1. Oxygen sensors
2. Coolant Temperature Sensor
3. MAF

You've swapped out the oxygen sensors.
You've replaced the Coolant Temp Sensor. (Part LHE1600AA, not DAC11079)

The remaining issue is either a bad MAF, which could throw a code, vacuum leak, faulty ECU, or ultimately a base idle reset.

At this point, I believe the base idle reset is your best bet.

 

I think your right.