My 2000 V8 S-Type has developed a stutter at idle and the engine sometimes blips at highway speeds. From what I am seeing on the forum is that this is common when a coil is on the way out. At 90,000 miles I don't want to play coil guessing games, so I'm going to replace all 8 coils and replace the plugs at the same time. So here's the question:

Does brand name matter when replacing the coils? For the 4.0, I'm seeing coil prices between $20-$44 on one site, Standard brand being the cheapest, while Beck Arnley is the most expensive. Has there been some hit and miss experiences with the cheaper coils? I just want to do this right the first and only time without overpaying. I'll be using the Bosch platinum plugs as that's what I've always used as replacements on all my cars.

Thanks in advance.

 

Keep reading and you'll see the non-OE coils often go bad so depends on how lucky you're feeling!

Have you put in the revised (metal-bodied) chain tensioners? When the plastic ones break, which they will at some point, your engine's a write-off sadly.

 

Definitely not going with the cheapo coils then, but where's the best place to get the OEM coils? Are they actually listed as Jaguar or a specific brand name?

I haven't done anything with the chain tensioners. I don't spend as much time on here as I should so I'm just not as familiar with the issues and trouble spots until something goes wrong and I'm on here getting information before I get my hands dirty. I'll have to look into it.

 

In the UK here o found the jaguar dealers were the best value for money for coils

 

I'll check with my local dealer. The dealer here runs an online parts store that typically has better prices and they have given me similar pricing when I've went into the dealer. That may be my best bet.

 

CRAP! $700 for 8 OEM coils...

 

I wouldn't change all 8 especially if you've not done the tensioners.

Idle problems are far more often air leaks. Check fuel trims (LTFTs).

 

+1 to Jag V8 regarding NOT changing all the coils at this point..

I personally do not believe in aftermarket coils. I go with either Jaguar OEM (XR827823) or Ford Motorcraft Coils.

I have also heard Napa has an Echlin coil with a 3 year warrranty - about $50/coil.

You can also invest in a COP tester - about $80 to see which coil(s) may be acting up - remember, just because the CEL isn't illuminated - doesn't necessarily mean one (or more coils) are intermittently misfiring.

Your symptoms certainly sound like a coil is on it's way out.

One more thing - if you find any evidence of oil on those coil boots - plan on getting the cam cover gaskets changed out.

But also, focus on getting those tensioners changed out - at the very minimum the secondaries...

 

I just swapped out my coils. Frankly, I am amazed the car ran with the old coils in place. 3 were outing out just 50v and a couple were pretty much falling apart.

The car now feels like it did brand new but since I am a bit of a novice, what's the deal with tensioners?

 

My understanding is Basically, the timing chain tensioners on the 4l are made of plastic, they fail and allow the timing chain to become slack.

The timing chain then slips a cog or 2, putting the top of the engine (valves) and bottom of engine (pistons) out of sync, this then alloys valves to come into contact with cylinders.

Valves hitting pistons is not good,you would need to replace the engine. (unless you could source all the parts needed, totally strip the engine and replace damaged parts, which would be more money and time and effort than replacing the engine)

This is my simplified explanation, if I've missed something I'm sure someone will post.

 

There are write-ups & pics on the site or failing that on jag-lovers.org