3.9l ls misfire's when warm with no codes

[lincoln_man]

when I drive the car when the engine is cold it runs fine when it warms up to operating temp it misfires underload and on the highway at low rpms when it is reved up with no check engine light or even a pending on the scanner. it has 94 octane some coils were replaced from the used car dealer also the valve cover gaskets were done and there is a mild exhaust smell coming into the car when parked the car can you guys help I am new here?
thanks

2001 lincoln ls 3.9l with 138000 kms

 

[cannons_custom]

I have no ideas on your problem man and i'm sorry but i'm sure someone here can help. I have to ask though...Where are you getting 94 octane?

 

[joegr]

I would start with taking the coil covers off and looking for any oil leak in the plug wells. Just because the gaskets were just replaced, it doesn't mean the new ones aren't leaking.

 

[lincoln_man]

I have no ideas on your problem man and i'm sorry but i'm sure someone here can help. I have to ask though...Where are you getting 94 octane?

Hey that would be great I just bought the car. I get 94 octane at sunoco I am from ontario

 

[lincoln_man]

I would start with taking the coil covers off and looking for any oil leak in the plug wells. Just because the gaskets were just replaced, it doesn't mean the new ones aren't leaking.

ok I will try that next time thanks.. I havent smelt any burn oil around the covers just alittle exhaust by the firewall

 

[Outkast]

sounds like coils to me. Mine did it only when warm also.

 

[joegr]

I should add to my previous response, that you'll probably save yourself some grief if you just bite the bullet and replace all of the plugs and coils.

 

[lincoln_man]

sounds like coils to me. Mine did it only when warm also.

yah i bought some ebay ones I will replace all of them next week what kinda spark plugs do you recomond?

 

[jeffyman215267]

do your self a favor and skip the e-bay coils and be sure

 

[Outkast]

do your self a favor and skip the e-bay coils and be sure

why is that? Plenty of people on ths site use the ebay coils all the time with no problems.

 

[gcwimmer]

yah i bought some ebay ones I will replace all of them next week what kinda spark plugs do you recomond?

Stay with OEM, the spark plug the LS motor is designed around. Change SP manufacture if you need to change the temperature range for say NO or supercharger/turbocharger.

 

[jeffyman215267]

Bought the e-bay ones,still had a misfire,had to go back in and change all to be sure cause you cant tell by looking at them,replaced with motorcraft had no problems again ever,i will sell u the e-bay coils for 50 bucks if u want them