1996 Bonneville, P0305, P0442, P1406

[jugstah]

A month ago, my wife took in her 1996 Bonneville for an inspection sticker, and got rejected. The codes were as above, p0305, p0442, and P1406. The guy ran a diagnostic, and told me that I needed to replace the EGR valve and the Vapor Canister.

I did so, replacing it over the weekend a few weeks later. My wife takes the car in for the inspection the next day, and it flunked. The guy tells my wife that she should have driven the car around for a few more days to allow the computer to reset itself.

Question, what else could be wrong if it's not just the EGR Valve and the Vapor Canister?

[GTP Dad]

The manual I have states that there is an engine misfire on cyl #5. That could be the problem that is causing the car to run too rich. Code P0305 refers to this problem. The other two you have already corrected. I would have the computer scanned again and get the codes cleared so that you can run it for a while to see if the codes reappear. If they do then find out what new codes are present at that time. I would also check the convertor since it may have gone bad due to problems with the egr valve. Also, check the lines running to the vapor canister. The P0442 code indicates a small leak, since you changed the canister the problem may be in the lines to the canister. Just a few items to check.

[jugstah]

Ok, great, thanks. I appreciate the quick reply. I'll have the guy run a diagnostic again, wish it didn't cost so much eaech time.. 30 bux the guy runs it for... i read somewhere here that autozone would do it for free?

[GTP Dad]

That is true, they will scan it for you for free and even reset the codes if you have corrected the problems.