Hi guys
Please can someone help me before I pull the remaining hair out of my head, I own a 2000 s type 4l v8 I bought it privatley and for a few weeks it ran perfectly, then it developed a missfire, I took it to a local garage that belongs to my nephew, he did all he could including changing the plugs the missfire persisted, it then went to DTM a Bristol diagnostic specialist, Swallows jaguar and NM jags and it still missfires.
So far I have had done:
new plugs, three coil packs, an engine flush, new fuel filter, four new injectors, cam position sensor, new plugs again, another engine flush, wiring checked by swallows and a small repair made, two new head gaskets and modified cam cain kit fitted, fuel tank flushed and new filter again and some more new plugs.
The symptoms are, rough running at tickover, rough running at low revs, intermitent engine warning light when motorway cruising, more developed miss at higher revs.
If you give it some wellie the missfire seems to clear for a second or two then returns.
Please if you have any idea what this could be, however outlandish, please reply, I am at the end of my tether and will try anything.
yours hopefully.
Big Garry.
miss fire
Moderators:GJS-typeR, Montana5
OK Garry. First thing worry not. There is a cause and reason for your misfires. It is fair to say we have seen most of the reasons and by and large know how to get around them.
Firstly, if you have a copy of the JEC March 2009 magazine, this will help you greatly. You will see that I`ve had the problem myself and cured it.
Secondly the problem came up as an item at the S-type Seminar this year. It would appear that worn and misfiring plugs cause coil failure if left for any length of time. Misfiring plugs kill coils dead! You have changed three as they were defective. I`m wondering if you have one or more old coils at burn out stage.
Thirdly, I`d refer you to my throttle body change article in the May 2010 magazine with the suggestion that a good read and understanding of the section on the throttle position indicator and throttle pedal sensor is taken in. Pedals do give up the ghost and pots on the throttle can fail. That can cause misfires on both V8 and V6 cars.
Fourthly, the March 2010 magazine also gives pointers for successful running of our cars. You will find that useful.
Cleaning of the throttle is important and can stop the butterfly plate from sticking due to crank case breather residue formation. Cleaning proceedure is detailed in the throttle article.
The above info should help you to get a good stab at sorting your problem.
You don`t mention the mileage that your car has covered, but I imaging it could have covered around 100k miles at that age. if the throttle is well sludged and that mileage has been covered, then it is certainly due for a clean out.
If you are still struggling with the problem after dealing with the above, or you don`t have the relivant magazines please feel free to contact me from the details in the S-type pages. You might find phoning for a chat useful.
Although daunting when these problems occur, most sort out fairly easily once replacement prime parts have been fitted. Best deals can be found for coils on ebay or by contacting companies such as Motorsportworld on the net. SNG Barrett are also good to deal with and are very helpful.
Come back to me if you get stuck.
Kind regards,
Mike Kennedy S-type Co-ordinator.
Firstly, if you have a copy of the JEC March 2009 magazine, this will help you greatly. You will see that I`ve had the problem myself and cured it.
Secondly the problem came up as an item at the S-type Seminar this year. It would appear that worn and misfiring plugs cause coil failure if left for any length of time. Misfiring plugs kill coils dead! You have changed three as they were defective. I`m wondering if you have one or more old coils at burn out stage.
Thirdly, I`d refer you to my throttle body change article in the May 2010 magazine with the suggestion that a good read and understanding of the section on the throttle position indicator and throttle pedal sensor is taken in. Pedals do give up the ghost and pots on the throttle can fail. That can cause misfires on both V8 and V6 cars.
Fourthly, the March 2010 magazine also gives pointers for successful running of our cars. You will find that useful.
Cleaning of the throttle is important and can stop the butterfly plate from sticking due to crank case breather residue formation. Cleaning proceedure is detailed in the throttle article.
The above info should help you to get a good stab at sorting your problem.
You don`t mention the mileage that your car has covered, but I imaging it could have covered around 100k miles at that age. if the throttle is well sludged and that mileage has been covered, then it is certainly due for a clean out.
If you are still struggling with the problem after dealing with the above, or you don`t have the relivant magazines please feel free to contact me from the details in the S-type pages. You might find phoning for a chat useful.
Although daunting when these problems occur, most sort out fairly easily once replacement prime parts have been fitted. Best deals can be found for coils on ebay or by contacting companies such as Motorsportworld on the net. SNG Barrett are also good to deal with and are very helpful.
Come back to me if you get stuck.
Kind regards,
Mike Kennedy S-type Co-ordinator.
My appologies Garry.
I missed that you were in Bristol. I lived there until last year.
PJG Autos at Longwell Green used to help me look after my V8. They are top guys and know their stuff. They helped me to fix my misfires and will have no problem clearing the wood out of the trees for you. Indeed, these guys were instramental in helping me write the "coughs and splutters" article in the March 2009 magazine.
I recommend this business to members within the Bristol/Bath area. No problems with them ever and you will not pay main dealer prices either.
Mike
I missed that you were in Bristol. I lived there until last year.
PJG Autos at Longwell Green used to help me look after my V8. They are top guys and know their stuff. They helped me to fix my misfires and will have no problem clearing the wood out of the trees for you. Indeed, these guys were instramental in helping me write the "coughs and splutters" article in the March 2009 magazine.
I recommend this business to members within the Bristol/Bath area. No problems with them ever and you will not pay main dealer prices either.
Mike
Hi thank you for replying to my plea of desperation and sorry I did not get back to you sooner, I am a new member and had trouble logging in.
I took your advice and had Used Jags. com, formerly NM Jags clean the throttle bodies, unfortunately it made no difference, there new diagnostic software says its pot no 3 but the new coil pack, injector and plug also made no difference.
As a new member sadly I do not have access to the articles you suggested I look at so any ideas are still welcome.
At the moment Used Jags.com are still trying to find the problem and I feel I should give them a fair crack at it but any expertise would be foolish to ignore.
Thank you for your recommendation of a good garage in Bristol they are on my list if Used Jags. com fail.
Finally thank you for your opening words, my mechanical knowledge is restricted to two wheel and two pots (Harley Davidson) and the big v8 was a little daunting.
Many thanks.
Big Garry.
I took your advice and had Used Jags. com, formerly NM Jags clean the throttle bodies, unfortunately it made no difference, there new diagnostic software says its pot no 3 but the new coil pack, injector and plug also made no difference.
As a new member sadly I do not have access to the articles you suggested I look at so any ideas are still welcome.
At the moment Used Jags.com are still trying to find the problem and I feel I should give them a fair crack at it but any expertise would be foolish to ignore.
Thank you for your recommendation of a good garage in Bristol they are on my list if Used Jags. com fail.
Finally thank you for your opening words, my mechanical knowledge is restricted to two wheel and two pots (Harley Davidson) and the big v8 was a little daunting.
Many thanks.
Big Garry.
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