Its hard to determine if the smell could be a leaking valve cover gasket that is allowing a small amount of engine oil to drip from the top of the engine down onto the exhaust manifolds.
Your Toyota has a distributor cap, spark plug wires and spark plugs and of which could cause the engine to run rough if they have failed.
Trouble codes are easily retrieved from this Toyota as it has OBD1 diagnostic capabilities.
Your Toyota has valves that have the valve clearances adjusted with "shims". If the valve covers are removed or a cylinder mis fire is related to low compression it is important to check and adjust the valve clearances. If the valve cover is off to repair an oil leak definitely have the clearances checked!