Toyota Repair: oil consumption, cylinder head bolts, surface flatness

Question
Hello,this question is about my sons 94 sr5 4wheel drive 3.0 v6 we have had it  for 1 year during this time oil usaage would vary from a qt every  1000 mi to a qt every 100 with a little smoke at start up on acasion but not always then  the engine starting misfiring it had a burnt ex valve #4 at the shop they completely reworked both heads  installed a new timming belt,pcv valve and plug wires, got it back and and 2000.00 dollars later it smokes like a freight train and in 30 miles has already oil fouled a plug ,compression was good in all cyls except the one  with the burnt valve, engine has no blowby but when i removed the clean air tube from the throttle body engine oil ran out. thx  hope you can help. Donnie

Answer
replace cylinder head is a very restrict job, I just mention some key points and you could double check with the technician make sure they did the job properly!
1. did they check the both cylinder head surface flatness, is it within spec. ?
2. if not within spec. , did they resurface the cylinder head?
3. before they install the valve, did they recondition the valve seat and lapping the valve
4. before they install the valve, did they test the valve spring and make sure it within the spec ?
5. did they replace the cylinder head bolts ?
6. did they find the reason why cause the valve burn ?

You could ask them try "leak down test" and the test will show you why #4 cylinder failed compression test. I think it could be 2 reasons, 1- exhaust valve not seated properly, bad valve seat or failed valve spring, 2 - burned piston ring.