172 Ph2 Wont idle

[sand6000]

I have recently changed the head on my 172 due to bent inlet valves. Now it won't idle. I have checked and rechecked the timing and am happy it is OK. I have swapped all of the sender units, TDC etc, etc but nothing alters. I have now swapped the dephaser and still nothing. The engine is running well at good throttle openings but a bit rough at cruise and stalls when at rest. Feels like fuel surge. I have also swapped over the injector rail and had the coil and plugs checked on a diagnostics unit and no faults are showing.
Any ideas please.
Pat (New Zealand)

 

[bloke]

air leak. get a smoke pressure test done. did you re use inlet manifold gaskets, if so did you use anything on them?

 

[sand6000]

I thought of an air leak but not had it tested yet. Will see what I can organise. New gasket as it came with the top end gasket set. You said gaskets (plural) were you thinking of anything else? I di not use anything on the gasket. Should I.
Cheers, Pat

 

[sand6000]

Can you tell me about the 2 vacuum hoses that come off in front of the throttle body (engine side). Where do they go and what do they do. One goes under the left guard near the headlight and the other larger one towards the firewall.

 

[Dan@SJM]

What timing tools did you use? Usually when they don't idle immediately after a belt change etc the timing is out

 

[sand6000]

What timing tools did you use? Usually when they don't idle immediately after a belt change etc the timing is out

Hi Dan, I have all the factory tools so can lock the crank, cams etc. Have checked and rechecked the timing and it always shows it to be OK, that is, I can locate the cam timing horseshoe in the slots when the crank is locked at TDC. Is it possible that the inlet valves on the head that I changed over are not closing properly? Would that give these symptoms?

 

[sand6000]

I have now had a compression test done and had a test for air leaks. Both normal. Could my problem be throttle body and if so how can I tell? There is nothing coming up on diagnostics checks.
Could the ecu mapping be out? I have the RS tuner RON98 program. Should I re-install it?