Car Questions

Clear all

Misfire at highway speed


Topic starter

Hey Scotty, 

Thanks for being here. Gr8 channel.

I have an 02 Trailblazer with 455,000 k on it. 

I am getting misfire codes at speeds above 35 mph. 

I replaced the ignition coils and plugs and truely the problem has become slightly worse. Now the board won't really clear and the codes are intermittent at various speeds.

The vehicle is sluggish upon acceleration and struggles to reach speed,not terrible hard but it is not answering the call the way it should.

Is it at all possible the ignition sensor could be malfunctioning? 

I not sure how to diagnose the issue.

I'd appreciate your advice mister.


(edited for language. -mod)

2 Answers
Posted by: @shavedkat

I not sure how to diagnose the issue.

What are the exact codes? Analyzing live data while the problem occurs would probably be a good start.

Low-hanging fruit would be filters and fuel pressure.


Keep the language clean please. Thank you.