So I have a 2004 ss with the 3.8L non supercharged and I’m have a problem I can’t figure out, the car has around 200k miles

The problem

so last week I had noticed a problem when accelerating, the motor starts to not was to keep accelerating and the rpm’s get jumpy around 3200 and runs fine after 4200; almost like it’s stumbling or something. I’ve been trying to get it to send a code and I got one today and it was for cylinder 3 misfire the only reason that came up is because when it started I went full throttle and it gave the a flashing check engine light

(also in neutral it revs fine it’s when it’s under load it will happen)

what I’ve tried so far

The cat was slightly plugged so I believed that it was plugged enough to give me problems so it was (stolen)

just today I tried the throttle position sensor but no luck

I just replaced the coils (helped a bit) I will be doing the wires and plugs later on in the week and also look for a vacuum leak.

( replaced the fuel pump when I first got it because I had no fuel gauge)


I may try to replace the fuel filter but I don’t want to keep throwing parts that I think are going bad , j have the service records from the original owner from when it was sold this year so I’ve been going down the list of possibilities