Lately my car has been stalling out after trying to start it again after it has been recently turned off. Could this be the fuel injectors or the oxygen sensor. I must admit, the car manufacturer suggest using high test gas but I have been using the medium grade… This condition is not consistent. It has bad periods and then it will be fine for a long period. The car has 108,000 miles. The oxygen sensor was already replaced around 70,000 miles. No other major engine work has been done to it.
Hot start problem. It could be a lot of things, but my guess something is wrong with the cold start injector or its sensor. It isn’t supposed to shoot gas into the intake manifold when the coolant temp is hot. I think it is, and the mixture is too rich to start the engine.
Could be a fuel pump problem too.
First off, quit cheaping out on the gas. The car calls for premium. If you don’t want to use premium, sell it and get something with a lower-compression engine.
Second, what year?
Idle Control Valve (IVC)?
Camshaft position sensor (CPS)?
Bad coils (post 150k miles?)?
Valve cover gasket leak?
Blown head gasket?
Could be a bad coolant temp sensor.