hello, I have a 2002 chevy blazer 4.3L 2wd with 230K miles. here is the problem: when i drive on the highway and i get to about 70mph or above, the vehicle will stop accelerating for a second and then go back to normal. at the same time the check engine light flashes. I got the code checked and they said it was a cylinder misfiring. It only happens when i get to 70mph or more. just a few weeks ago i had the wires, plugs, cap and rotor changed and it still does it. could this have anything to do with the catalytic convertor? I took it to car-x and they couldnt figure out why its happening, so i just had a radiator flush and new thermostat, and ball joints and brakes all the way around because it was needed. I just cant figure out why its misfiring. Ive been trying to do some research online to find the cause, but the only thing ive been told to do is change the wires, plugs, cap, and rotor, which i did. so if anyone has any ideas why this could be happening, please let me know. im willing to try anything. Thank you!

 

Are you committed to obtaining the tools that you will need and doing the work to correct the problem yourself, or are you just fishing for things to tell someone else to do? What is your mechanical experience? It makes a big difference. Freeze frame of engine sensors when code was set is a good place to start. Guessing on modern engines, followed by shotgunning parts is typically pointless and can cost a lot of money. A proper diagnosis is in order.

Question is who is going to do the diagnosis? If you want to do it we can help. If not you, then you will need to find a good shop. They don't come cheap... you will pay for their experience, expertise, and equipment.