Originally Posted by 5Ohhguy
It smells like fuel not sweet like coolant i looked up on it as i mentioned before i have the cts thats probably bad (code 21) which i heard can be problematic for hot starts causing the engine to use up to much fuel. Anyways code is popping up might as well change it to see if it helps.
Was the engine cold or was coolant temp below 50° when you ran the koeo test and/or was coolant temp below 160°,when you ran the koer test??
If the answer is yes,that's what caused code 21 to be set.
If no,test the ECT sensor while the engine is cold then retest it when the coolant temp is above 160°.If the ohms value for a given temp matches the chart below,the ECT sensor is OK & you'll need to test the two ECT sensor wires for continuity, between the sensor & the 60 pin connector.
When you say rough starts,I assume you mean its a hot no start issue??
When the hot no start occurs, hold the gas pedal to the floor while cranking the engine.Does it start now??
If yes,youve got a leaking fuel pressure regulator,leaking injector or a weak fuel pump.
If no,cycle the key on/off 5-6 times then try starting it.If it starts,the fuel pump is weak.
If these tests don't cause it to start,pull the spout plug then try starting it.If it starts,the pip sensor is going bad.A defective tfi module will also cause a hot no start.
A lean O2 sensor code can be caused by numerous things.A vacuum leak is the main cause,but you can click on the link below to see all of the possible causes.
As far as your car smelling rich goes,when the o2 sensor reads lean,that causes the ecm to (falsely) richen the AF mixture to bring Afr back to normal.
Be sure to check your grounds too.
1) (-) battery cable to block
2) ground strap between driver cylinder head & firewall
3) EEC ground next to the windshield washer reservoir.Check the wire & the round black connecter too.
Here is a link that details the different strategies that occur during all running modes.
Fuel Injection Technical Library » Strategies
O2 Sensor Codes 41/42/91/92 Troubleshooting