Giving as much detail as i can. I have a 2002 jaguar s-type v6 roughly 158,000+ miles and the car will idle rough. It does it in the morning and if the car has been sitting still for a while (temperature plays a part). I have had a tune up (spark plugs changed(not cheap ones), oil changed, valve cover gasket changed, did a gas treatment, cleaned the throttle body, replaced bank 2 vvt solenoid, both catalytic converts changed, coil packs (need to replace 1 p0304). Yes its a lot but it was not done all at once . When codes come up I jump on the problem right away. I am at a lost of what else could be going on. This morning it rough idled and the battery symbol flashed several times and the car was acting as if it wanted to cut off but then it revs back up and battery symbol goes away. The battery symbol does not flash all the time just when the car is cold.

There are no codes on now but when you press the gas the "get up" power is a little sluggish.

Any thoughts.

 

You're sure it's a battery symbol? (Check handbook.)

 

Yep, the battery symbol lite up then went away. Not the first time it has done that, mostly I get the rough idling.

 

Check to see if the alternator belt is slipping and then check to see if it is functioning correctly. If that is ok check the battery voltage at the battery and at the cigarette lighter because it looks like you have a charging problem.

 

+1

and check power/ground connections

 

Thank you guys for your input, I will look into those suggestions. Will these suggestions have anything to do with rough idling, because like I said earlier the battery light blinking is few and far between.

 

Maybe. Can't run right unless power is perfect.

 

Got a code reading and found out it is the p1388 code bank 2. Replace oil control valve (OCV).

 

Fix power first. It's electrically operated.

 

When you say fix power first what exactly do you mean? I really want to fix the issue, i just need to understand.

My first step was to get an oil change and switch to a heavier oil 20/50, should I not do that?

Thanks!

 

Your electrical power issue is far more serious.

 

OK, outside of the electrical power issue you are referring too, would getting a thicker oil change be a great idea and after that what would be the next step to solve the p1388 issue.

 

No keep to the recommended oil grade.
Have you downloaded a copy of the JTIS from the stickies? THis will tell you how to check everything.
As your car has a relatively high mileage I would suspect that the belt is worn out. Jaguar recommend that it should be replaced every 80000 miles. The easiest way to test it is too look at the adjusters and are they at the max adjustment.

JagRepair.com - Jaguar Repair Information Resource

DIFFERENT ENGINE BUT THE PRINCIPLE IS THE SAME.

If this not the problem then check what charge your battery has should be 12.6 volts. If not recharge over night and if still too low buy a new battery.

If good. Then check the charging voltage. The safest way is to us an elm327 and use a program that will show that will show you the voltage when the car is running.

 

Just read JTIS and it says to check the auxiliaries belt.

When the car is running get somebody to press the accelerator pedal and you should see the tensioner moving to keep the belt tension correct.
That will tell you if the belt is worn out or if the tesioner is no longer working also look for skid marks on the alternator wheel and any other wheels they will show you if the belt is slipping but I would expect that you would get a screaming noise if this was the case.

 

Thank you Ducmon for breaking it down, I will have the mechanic check the auxiliaries belt, since i do get a whistling noise but it goes away after a while. I will read check out the link you sent.

In addition I have ordered the vvt solenoid valve since that's the code i was getting. Like said earlier in the post I replaced the solenoid on bank two but that part was from a pull a part.

I will keep you posted. Thank you again.

 

The winning noise means that you need a new belt download JTIS it will help you a lot and save you money too.

 

A belt squeak that goes away after warm-up is likely to be a delaminating crankshaft damper, which could also impact alternator functionality.