Hey Scotty, I have a 1994 Toyota Celica ST 1.8L with 145,000 miles. Diagnostic doesn’t throw up any codes but starting the car, the idle is really rough, jumping up and down from 1000 rpm to 200 rpm quickly. After a while when the car warms up, the rpms settle but still sounds harsh. It will not pass smog. There’s also a gas smell when this happens. There’s also a ticking/pinging noise coming from the top end of the engine. I replaced spark plugs and replaced the idle control valve, throttle body gasket, cleaned throttle body, replaced pcv valve. Please help me figure this out!
Well so many things can do that. I mean if the ticking noise is really loud you could have a bad valve. Bad cam all kinds of things. So start by doing a compression test of the engine to see if the engine is physically worn out. If not often fuel injectors are old and they leak and you just need to replace them
