Discussion
When I fire her (XK8 1996) up from cold she drives like a dream but after about 1 mile or so, I get a fault on the dash "Poor engine Performance" and "engine fault" and she runs as though down a cylinder or two.
I changed the MAF sensor for one believed to be good and it made no difference ??
Anyone have any ideas ?
Louie
I changed the MAF sensor for one believed to be good and it made no difference ??
Anyone have any ideas ?
Louie
Could be worth checking:
Inside of the throttle body and the butterfly valve for a build up of contamination. Clean out with carburettor cleaner.
Check all the vacuum and breather hoses are OK.
Check the part load engine breather on the left hand cam cover is not blocked. Very carefully and gently clean it back out to the correct size with a 2.5mm drill bit.
Remove the plugs and check them all for uniform colour and correct gap (1.0mm) Change plugs if close or overdue.
Oil change - even if not due. Really degenerated mineral oil will allow a loss of compression when hot. This on its own is not likley to be a problem in a otherwise healthy engine but in a worn one it may be. There's also likley to be excess oil mist from heavily contaminated oil too which can affect combustion - again not usually a problem if the engine is good but if the oil has got that bad - and it may well have done in less then 10000 miles - then it's essential to change it.
Disconnect and reconnect (to clean the contacts) all the electricial components under the bonnet.
None of this can do any harm and is only elimating potential problems a garage will suggest anyway.
Check all that then take it out for a fast drive to get it really hot.
If you still have a problem then get it scanned.
Inside of the throttle body and the butterfly valve for a build up of contamination. Clean out with carburettor cleaner.
Check all the vacuum and breather hoses are OK.
Check the part load engine breather on the left hand cam cover is not blocked. Very carefully and gently clean it back out to the correct size with a 2.5mm drill bit.
Remove the plugs and check them all for uniform colour and correct gap (1.0mm) Change plugs if close or overdue.
Oil change - even if not due. Really degenerated mineral oil will allow a loss of compression when hot. This on its own is not likley to be a problem in a otherwise healthy engine but in a worn one it may be. There's also likley to be excess oil mist from heavily contaminated oil too which can affect combustion - again not usually a problem if the engine is good but if the oil has got that bad - and it may well have done in less then 10000 miles - then it's essential to change it.
Disconnect and reconnect (to clean the contacts) all the electricial components under the bonnet.
None of this can do any harm and is only elimating potential problems a garage will suggest anyway.
Check all that then take it out for a fast drive to get it really hot.
If you still have a problem then get it scanned.
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