Hey guys.. I'm having an issue with my 96 xj6.. Upon a cold crank I'm feeling what feels like I miss at idle.. It's a kind of sputter as I pull off and the engine will cut off when I come to a complete stop. At least until I've been riding for about 15 min or so.. After that it idles and runs fine. It'll even cause the trans light to illuminate once I have kind of drive with two feet to keep it running.. I've changed my plugs and I've checked all of the coil packs. All of which are firing.. Is there anything anyone can sugge5that I trouble shoot for..?
side note: The car cut off about a week ago and would not start. After checking for gas and spark I found that I had come across some bad gas or either water was getting in the tank somehow.
I subsequently hooked up a separate fuel pump to the fuel line to suck all of the gas out and even threw in some gas treatment/water remover into the tank before adding gas again.
After a few tries it fired up and has been cranking every since. But still with the rough idle and sputter in the first 15 min or so of driving. After that it seems to smooth on out But still has somewhat of a miss here and there..
Any suggetstions..?

 

 

Contaminated fuel is always one of my first concerns whenever rough running happens. I've seen bad fuel several times over the years. So you did well to change it out. In recent years I use Shell premium almost exclusively, and it has always been good. Knock on polished burl walnut!

Worn spark plugs are known to cause random stalling and the need to drive with two feet! What kind of plugs and coils did you use as replacements? The engine is somewhat sensitive to spark plugs other than original Champion types. Aftermarket coils are notoriously substandard compared to the original Diamonds. Coils are one of the most frequent subjects here.

You might need a new Crankshaft Position Sensor (CKPS). All these cars need a new one at this age, especially with higher mileage. It is a maintenance item at about 100k miles. It is hard to test them accurately (coils as well). So replacement is easiest and aftermarket CKPS units seem to be generally reliable.

 

 

Spend about 10 bucks on an obd tool. Read the error code on your phone and you'll know exactly what to do next. Easy..

 

I'm assuming there's no Check Engine Light. The transmission light will come up when the engine stalls out. That can most likely be ignored...unless your transmission fluid is low.

 

Mine stalled. With the transmission light coming on. No check engine light but found codes that suggested issue with o2 sensors..

Nevertheless I think the first thing to do when you buy these cars is simply to get an obd tool. It's cheap it's easy and you'll be able to pinpoint a lot of potential issues instead of " wasting time" on forums seeking advice from experts who only can guess what the issue is.

 

Not from personal experience, but a distant recollection that stalling and transmission light on can be caused by low trans fluid. Doesnt' cost anything to check ........

 

It absolutely can.

 

I am often surprised how many people do not have simple OBD2 readers for their cars. If your car has OBD2, I'd say it should be the #1 item on any owner's list, more valuable than a service manual. (which should be #3 on the list, right after joining this forum at #2)

 

Spot on... 👌🏻

 

There is no doubt in my mind that you need a new set of coils and spark plugs. Coils you get on eBay will only last about a year. Don't buy from a Jag dealer. Do a search on coils. Last I read a company in that business is now making good coils for these coils.