Just replaced the headgasket on a 96 Honda accord non vtec and now im having problems again with it. Car starts, but its hard to start, the engine sounds rough, cars overheating a bit, seems like its misfiring, exhaust smells fuel rich. Check engine light is on pushing out 41 code for Primary Sensor Error. My friend told me it could be my timing belt is off. Is this true or is there any other answers?

 

Check?

Again, re-check your work - timing, valve lash and connections. I'd also suggest a compression test.

 

like poorman said, compression test it...head gasket/head rebuilds don't often work out right

also could be an exhaust leak at the manifold or anywhere you opened the exhaust