Timing belt alignment problem

[Dehabur]

OK I have done all that Dr J has indicated in the DIY sticky. Set timing on TDC marks, even got the Haynes book to assure correct position. Engine started right up. Timing light showed timing was close with service wire installed. Adjusted timing and engine idled fine until the engine warmed up. Then it was missing and so I adjusted timing again the motor idled smoothly but hesitated when revved. So took it on the road for a test and it ran terrible. missing with little power. I am tearing down again to inspect and verify timing marks. If they are correct am I a tooth off? If so which way do I move the belt. Got new dist cap, wires & rotor too. So where did I go wrong? Anybody got an idea what to check?

[71Corolla]

I'm not sure if you are confusing ignition timing with camshaft timing here. But it does sound like the camshaft is out one tooth. You need to have it exact, you can check the camshaft without taking everything apart, just remove the top timing cover, set the crank pulley to exactly zero degrees, and check your camshaft marks.

[Doctor J]

i would suggest to line up camshaft marks first (hole to the bearing) and then checking the mark on the harmonic balancer relative to the timing scale on the plastic timing belt cover. If belt timing is off (cam is one tooth late relative to crank), the mark will be at 15 degrees AFTER 0 on the timing scale

[Dehabur]

Dr J all marks checked out and lining up as described so moved 1 tooth eac way and still ran rough. I am installing this morning new plugs this morning with timing marks @ TDC. Will let you know how I make out. Thanks for your help!