Sign in to follow this  
kartRacer

Mystery Persistent Misfire

2 posts in this topic

I was given a 2002 automatic with 160,000 miles that's basically running on 4 cylinders at anything less than 2000-3000rpm. Its throwing codes P0305 P0302 P0316 and P0171, so cylinders 2 and 5 seem to be the issue, but I haven't been able to figure out why. The plugs on cylinder 2 and 5 looked pretty dry and are characteristic of a lean condition, but the electrodes and plug wires looked good and had decent spark. So I was thinking fuel injectors, but both injectors tested fine and after swapping them with a couple used but known good ones there was no change. I also checked the coil pack with a multimeter and all the resistance values were within spec. Also checked compression and both cylinders were good. I'm pretty much stuck at this point and not sure what else to check, any ideas? Could a vacuum leak cause a lean condition in a specific cylinder like that? Any other sensors worth investigating? Could it possibly be a timing belt issue and the valve timing not being correct? The previous owner said they had took it to a shop and they said she needed a new pcm, but I haven't found any reports of a bad pcm causing these issues and the car seems to function fine otherwise. Any help/suggestions are appreciated.

Share this post


Link to post
Share on other sites

A common problem is the spark plug wires go bad at higher mileage, giving a misfire at low rpm, even if they look good. I would replace them, with NGK blues.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this