I had previously posted a thread about the misfire, but was not able to get to a conclusion, the codes I got were P0301 and p1316, i have replaced the spark plugs, ignition coils, injectors, and on several occasions have moved them around but the misfire always remained on cylinder 1. the car shakes at cold start up for 30 sec and then stops, but once warm, it does not shake when you start it up. i recently checked the compression on each cylinder and got around 200 psi for all of them, i realize that it is too high but i have a feeling it is the compressors tester Gauge that is showing too high. i thought that since all the cylinders where around that number that i have compression in there.

Was wondering where to look next as I am running out of tests to do. thanks in advance to all

2005 Jaguar X type.

 

The cause of the misfire can also be a vacuum leak or a fuel injector that is not spraying correctly.

 

Thanks for the reply, but i have replaced all 6 injectors, and so i doubt that its the injectors because it showed a cyl 1 misfire before and after the replacement.

Also wouldn't the vaccume leak affect more than 1 cylinder. i just have a cyl 1 misifre code and the code p1316

 

NBCat + on that vacuum leak. Chased a misfire and found it to be a leak at the manifold gasket. Spray carb cleaner around the upper manifold joint while its running and observe if it is drawing in the celaner.

 

It is possible to have a vacuum leak from the sealing ring on the fuel injector, or from the inlet manifold gasket.

Did you replace the inlet manifold upper and lower gaskets and the IMT o-rings when you had the manifold apart?

 

Since you seem to have covered most areas it would seem to be manifold seals possibly lower one or IMT O rings if not already changed.
Fel pro do them dirt cheap at RockAuto? so change them all!!

You guys in the states are real lucky the price of non oem stuff is real cheap?

 

Just remembered the FelPro upper gasket set includes the 2 IMT Orings?

Part numbers below:
MS96485
Intake Manifold Gasket (4016.93.0090)
MS96494
Plenum Gasket (4016.93.0090)

This is sets of 6 each plus the 2 orings

 

While the aftermarket gaskets and seals may fit correctly, in my experience they tend to fail earlier than the original Jaguar items, especially the cam cover and spark plug boss seals.

Given the amount of labour to remove the manifold, it seems better to use the OEM parts whenever possible.

 

Thanks for all the reply's, but sorry I forgot to mention that I did replace all the gaskets, the top and bottom ones for the manifold, and both the IMT-O rings, i doubt its from a leak, beacause in my past experiences I would be able to hear out most air leaks and track it, but the car only shakes for the first 30 sec at cold start up, after that sounds normal, and runs normal.
I have offset the engine code after each time of service, and it always gives me the same 2 codes.
I was wondering has anyone ever gotten just 1 cylinder misfiring from a bad O2 sensors, or does that usually trigger all to misfire?

 

O2xtype05: Try this..... Carefully examine the electrical connectors and wires to the #1 coil and the #1 fuel injector. Look for anything, a bent connector pin, damaged wire, or loose electrical connection that could disrupt the electrical signal to only the #1 coil or #1 injector.


Why would the misfire occur only when the engine is cold, and not when it's hot? Perhaps engine heat & thermal expansion improve the electrical connection? Just guessing, but you've already tried the usual suspects.

 

Just examined all the wires, no wire showing, nothing looks suspicious enough to replace, the wires for cyl 1 look better than a couple of the other cylinders.

And well the CEL for the misfire comes on during driving, but i dont notice any changes in performance, i just mentioned that at cold start up the car shakes a bit to give more details about the car. which only continues for 30 sec and once the rpm drops to normal, the car stops shaking, and operates normally.

also, sometimes when driving on the highway for a while at an avrg speed of 55-70, when i stop, the rpm goes lower than normal, shakes a bit as if it wants to turn off, but has never turned off and it immediate boosts its rpm up to normal, is that normal? considering it is a manual car.

 

Was wondering since these cars have individual ig coils for each cylinder, do they have individual relays or fuses for each cylinder?, maybe i have a bad relay or bad fuse?

Thanks in advance to everyone,

 

Try taking a look at your throttle body. When I was replacing my gaskets and IMT O-Rings I accidentally unplugged one of the wires from the throttle body assembly. It wasn't the connection that was terminated but the wire came out of its socket. I ended up ordering an entire throttle body and only after installation did I realize my mistake.

Either way, good luck. Hope you find your issue sooner than later.