1992 manual na cars running really rough no power then power comes back,garage say both o2 sensors gone and one coil pack,im hoping the ptu has'nt gone are they expensive and what symtoms happen if it has failed.

If the ptu has gone you will know about it. Check that you have spark to each coil pack, if there is a duff one, try one that is known as a working, then check all connectors to coil packs and injectors, give em a good clean with a small file, and check they are seated correctly. Post up if anyone local has a spare working ptu.

Very common prob on the zeds. Have a look over the MAF connection and do the same

 

If found ptu is messing about, which it sounds like it is. have a look at this

 

[ http://www.courtesyparts.com/Mercha...ode=22020-00Z32 ]

Duff ones are the best ones

Andy you would like my number plate then lol

1992 car would have a series one PTU?

 

Can pick em up for peanuts

failed o2 sensors will affect running but not greatly noticable..rough running will be mostly down to the dropping cylinder. Used S1 PTU's readily available for around £30, or you can get a more reliable S4 PTU for around £120 new.

 

May not be the PTU though - There are common issues with wiring and connectors. You need the fault properly diagonesed first. There are lots of threads on there the same faults if you want to do yourself.

Try simple things first, have you checked the water temp sensor connections ( yellow one on top of rad ) this causes all sorts of rough running: just clesn connectors or replace if really bad.