I bought a Bora 150 a few weeks back. I have issues with erratic idling and lumpy accelerating in higher gears at lower revs.
The first person I called said it was e worn camshaft, i checked and yes there was a bit of wear. So £300 spent and new cam fitted. I still have the same problems.
Managed to talk to the previous owners dad earlier, the reply is, it's loosing compression on number 4 cylinder and possible causes are burnt out valves or damaged head.
What can i do to check and possibly fix this problem the lololocost way.
Help please. Brad.

have you checked all hoses for splits?

I think the previous owner had already patched up all hoses in an attempt to fix this problem.

Sounds like what I had. Granted it was on an older 1.9TD, but principle is still the same.

I'd suggest checking for air/fuel leaks in the hoses as mentioned above. Get some clear fuel hose before the injection pump and see if it's got bubbles in it.

Replace the fuel filter as well.

Apparently its already had the compression test. What would cause low compression.

Cylinder head gasket or worn valve/Rings

Have you checked the EGR valve

I have checked the EGR valve and cleaned scraped it out so the valve moves smoothly with no change at all.
Who invented that bloody EGR thingy, what a crap design.

Sounds like it could well be EGR related.

One possible cause mentioned was filling up with unleaded burning out the valves, that would be a simple fix wouldn't it.

no, that would mean new valves which is a head off job.

Your best bet is to take the car back as private of business sale its illegal to sell a car that you know to be faulty without disclosing the faults to the buyer.

If you wanted to find out why the compression is low you could do a compression test, then test again with a squirt of engine oil down the plug holes. If the compression comes back then it is rings, if the compression stays low then its a valve seating issue or head gasket failure.

I would take what youv been told by the previous owner with a pinch of salt. What do you mean by the pipes have been patched up? PD's with any air leaks in the intake system will run poor.

Have a compression test done yourself so you know. The pd engines arnt as bullet proof as the older tdi's.

Does it smoke? have you had it plugged in to check fault codes??

The PD's do suffer with worn camshafts and that will knacker the valves if left for a while.

Unleaded in a diesel would burn the valves if its run on it for ages so i doubt its that. Itd do the pump first i reckon.

EGR, valve timing, air in fule system, intake pipes, MAF theres loads it could before before you pull the head off. The first thing id do is give it a fuel filter then get it plugged into vag com.

[Edited on 5/5/10 by Danozeman]