Hi All,
On my 2000 XK8 Convertible with 67,000 miles, after replacing my intake manifold in November with a used one (my mechanic said it leaked like swiss cheese), I continue to get more than occasional P1316 excessive misfire and P0302 Cylinder 2 misfire.
Replaced Spark Plug and Ignition Coil two times with no change. It usually seems to happen at lower RPMs. Bad stuttering near 2000 RPM. I was reading about adding K-Seal to cooling system to Repair
possible small cracks in the intake manifold. I don't see any coolant leaks at all. It may run fine for three or four days, then terrible for several days. Any ideas from anyone would be appreciated.

Much thanks,
Eric "erjent" Jordan
Punta Gorda, Fl.

 

What does a REPAIR to the cooling system have to do with the intake manifold?

Could an INJECTOR be faulty with the used replacement intake or did the original injector set transfer to the replacement intake?

 

Swap cylinder 2 injector with an adjacent cylinder and see if the misfire follows the injector.

Do not put crap in your cooling system for any reason.

 

Maybe try a smoke test on the intake system? Your replacement part may be faulty too. There are plenty of videos on how to conduct a DIY smoke test. Good luck.

 

Did it already. Same result.

 

That was my question too, but I've read several things that say yo do it.

 

Did which, moving the injector? If the misfire does not follow the injector then you may have a wiring fault in cylinder 2, or a vacuum leak. A good smoke test is the best way to check.

 

New injector and O ring. Moved the spark plug and Coil to Cyl 1. I am also getting occasional misfires from Cyl 5 along with 2. I'm kind of suspecting the manifold itself.

 

Misfires on multiple cylinders is often a vacuum leak or possibly low fuel pressure. I think low pressure would cause misfires on more than one or two cylinders.

 

I replaced the fuel filter too.

 

Have you inspected the air intake pipe that goes from the filter to the throttle body? They develop cracks in the accordion section, particularly on the bottom. Has your mechanic checked the fuel trims?

 

^^ This....

 

I did have cracks, looked more like chew marks. I epoxied them. I should reckeck.

Much thanks!

 

It would have to be really, really clogged. The only accurate test is to attach a pressure gauge to the Schrader valve on the fuel rail. But my money's on a vacuum leak.

 

I concur.

 

The Mina Gallery aluminum intake tube kit is worth every penny. No more plastic accordion section to split and crack....

 

I've been through this, it's like a whack-a-mole game! I had my intake pipe off and for life of me, couldn't see any cracks. Finally took it to a local shop who did a smoke test and sure enough, it was indeed leaking in the accordion section. Although pricey, I wanted to keep the car original and the shop was able to source a new old stock intake pipe.