i have a 2001 p38 4.6 vogue with a miss fire problem when load is applied it ticks over without missing a beat but as soon as you accelerate the engine miss fires like mad. i have replaced the plugs and ht leads but it is still there, any idears ?" need to get this sorted as cheaply and as quickly as poss as have just sold the car

Maf sensor...coil pack...air filter...park up open bonnet in dark rev engine and look for ht lead shorting out.

Could be fuel starvation... Had a similar problem with an old Vauxhall years ago, the cause of which was discovered by pure chance - on suspecting fuel starvation, I removed the pump (piston-rod type, driven by an eccentric on the camshaft) and manually operated it - full stroke pumped what looked like a good solid squirt of fuel. On the car, however, the rod was jamming 1/3 of the way out... And only spotted because it was mounted right next to the oil filler cap and could be seen working (or not, as it happened) with the engine running and filler cap removed!

Long story... but one with a point. If you have, or can get hold of, an inline fuel pressure gauge, test the rail pressure at idle and under load.

Also look for vacuum leaks. A simple OBDII code reader should give you any generic codes stored in the ECU, among which, IIRC, are 'lean mixture' flags that may not necessarily throw a CEL.

I recently had a similar sounding problem, turned out to be the fuel pump. Got one at a decent price from the guys at Mansfield.

Miss fires like mad eh?

Pull the crank sensor & check it for damage. Rule out mass fly wheel damage.

To the OP, did you get an answer to your issue?

Another one hit wonder

and they wonder why we don't take kindly or quickly to newbies

dogsbody said:

Another one hit wonder

and they wonder why we don't take kindly or quickly to newbies

Click to expand...

I know I don't post a lot and more than half my posts have been 'aaarrgghhh help please' type posts but at least I do try to give a little back. It's not hard.