99 GT Misfire on cyl 6.

[mazzafamily]

Hello everyone,

I have a 99 grand prix gt with the 3.8. What is going on, is that when the fuel tank hits 1/4 tank, the car will run roughly, making the Service Engine Soon light will blink and then go solid ON.

I took the car to Auto Zone to get the code read. While he was hooking it up, his was thinking evap code. It wasn't.

It was a Cylinder Misfire on #6. The guy thought it might have been a sticky injector since it is intermittent. Or maybe a plug or wire.

Any other ideas, or should I start with the injector, plug and wire?

And if it is an injector, what's the cheapest way to fix/clean it? I tried the in-tank additive and it doesn't help.

Thanks!

 

[a98gtp4u]

if its the injector just replace it. start with the cheapest thing 1st then go with the injector if need be.

 

[matt5112]

if its the injector just replace it. start with the cheapest thing 1st then go with the injector if need be.

X2

plug, wires, injector

 

[mazzafamily]

I'll start there. Thanks for the help!

 

[TheOtherNick]

Check the fuel pressure when your tank is low. I bet you have a week fuel pump and you are losing pressure since this happens when it is low.

 

[ARFF22]

Does you car have those aluminum heat shields with the springs around the spark plug wire boot? Mine did and one of the wires on my car just kept wiggling a little loose and which caused the wire to arc through that metal heat shield causing it to ground out and run like crap. Also caused my SES light to come on once and a while. I finally just removed that heat shield from that wire because it always happened at the most inconvenient times. Best way to check for it is at night, pop the hood and look down the at the spark plug boots, you will hear and see the spark. But don't try to push the boot on with the car running, I found out the hard way. The spark coming out of that wire has a little kick to it! Cheap easy check that won't cost you anything but time. Good luck!