• Welcome to the Land Rover UK Forums

    You are currently viewing the site as a guest and some content may not be available to you.

    Registration is quick and easy and will give you full access to the site and allow you to ask questions or make comments and join in on the conversation. If you would like to register then please Register Now

P38 Running lumpy


Accelerating Away
A 4.6 P38 on a N plate, just been serviced (new plugs, leads, etc,etc) but its still sounds like an industrial sowing machine. Its done about 120,000 miles so it could be cam shaft wear. Have given it a sniff test and no C02 evident in coolant. Any ideas anyone?
Well that helps,its probably failing oxygen sensors.Do you know how to test them ? Really a 10min session on Testbook is the answer,it would also give a chance to reset all the Ecu adaptions - this makes a huge difference to how smoothly they run,esp if it hasnt been done in a long time.
Hi Jon
It has just been on test book to cure an air susspension fault and nothing else showed up. Do you (or anyone) have a diagram or text of the order of the HT leads on the coils just i got one wrong when changeing them.
Looking down on top of the engine from the front looking to the rear,from the left it is, 2,3,4,7,8,5,6,1.
Dont forget the cyls are numbered across the engine so bank B,(drivers side RHD) is 2,4,6 and 8 - from the front going back and bank A is 1,3,5 and 7.(passenger side)
Thanks john. I have checked them and they are all ok. Do you think it could be one of the coil packs gone down? or any other ideas?
Usually there is visible damage to the coil packs,the plastic swells up and spews out the side.Or the tops burn off and crumble away.Dont often just stop working,do you have an inductive type timing light ? You could hook it up to each lead in turn and see if it flashes strongly on each cyl.Are they good quality leads? Cheap ones cant handle the high voltage too well and often give misfire issues even when new.
Have alook at all the plugs too,any that look a different colour or are wet will point in the right direction.
Post back what you find,Good Luck.
Hi Jon
After further investigation and a lot of head scratching i decided to take the plugs out and chec/clean them only to find that 2 of them had no gap! So i opened them up a bit refitted them problem solved. Now ticks over and pulls like a train. Still has a slight vibration from engine under heavy acceleration but i thick the cam realy needs changeing but its going up for sale so don't realy want to go to the expence of doing that. Thanks again for all your help.
Top Bottom