lower

Depends on how badly bent.

I'd be doing a compression check first and checking all the ignition connections.

Ultra_Nexus

No because the bend won't be like a banana, but be very subtle - fractions of a mm.

Due to the tolerance engines run at, it may be enough, especially when warm.

Wish I could say for certain - only way is to strip down

Take the rocker cover off and crank the engine over by hand.

Have a look at the valvesprings on 4 - see if they follow the cam lobes.

Should be a very easy test to see a sticking valve.

pistonbroke

Surely, the sticking valve idea would have been more prevelant when the engine was first installed. You've been running it since then and its been fine.

Have you been thrashing the crap out of it?

s2000tim

Ill see what the compression test comes back with I guess.

s2000tim

No, ive been really easy on it actually, only had it 2 days and been commuting in it both of them so been stuck in traffic alot to be honest.

Ultra_Nexus

I think that's what it needs TBH.

s2konroids

Bad luck mate.

Hypsonic, reasoning makes more sense

simonprelude

As to some of the other posts on this thread.................

Most people wouldn't even notice an engine running on only 3 cylinders.
It's not that obvious to be honest.

But yes, sounds like it needs a good flush, compression test and then a good thrash.

s2000tim

It sounded like an absolute bag of shit on 3, sounds perfect on 4.

pistonbroke

hmmm, its strange because its intermittant. Usually mechanical failures (even heat related) are constant. Yours being a running fine one minute, to hardly running at all the next.

I think the problem is electrical, rather than mechanical.