Hey guys I have a 1997 Pontiac Bon SE and have been having one bear of a day with it. First of all check engine light is on. Code read random cylinder misfire other code read rich or lean on one engine bank only. Now when I can get the car to start the acceleration seems to lag a little as I really press on the gas also cause the check engine light to flash while driving. Next once car has been driven for a while it does not want to start. Cranking is not a prob and sometimes it starts but idles very ruff then dies off. If I let it sit for a while sometimes It wil start up with a little ruff idle then things seem to be okay and I am on my way. I have replaced the upstream O2 sensor and have the downstream on the way. However deep down inside I feel that the 2nd O2 sensor is not the problem. Took the mass air flow sensor off and same problem(have not replaced) . I really don't even know how to start troubleshooting this bad boy. It seems everyday brings about a new little problem. Each sensor I read about is racking up some serious change which is growing less and less in my pocket. So do you guys think this sounds like a O2 prob. Maybe a Mass Air Flow Prob, Maybe I just need to scrap it and start with a new car. Any thoughts or suggestions would be greatly appreciated.

Welcome to the Bonneville forum. From what your saying it sounds like you have a vacuum leak. Take a can of carb cleaner and spray it around all your vac lines while the engine is running. Make sure you get the EGR tubs as well. If the RPM jumps up, you found the leak.

Hi SAM8872 - Welcome to the Bonneville Forum!

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Thanks for the quick responce. I did go out there and spray starting fluid around all the vaccum line I could see. I did notice a crack in one of the sleves that plugs into the throttle body. It seems as if it might be sucking some air from there after saturating the crack it finally increased the RPMS. As far as the "EGR tubes" I am not for sure what/where they are. And do you think this small air leak would cause the engine to not start(mainly when its cold 25 below or when the engine is Hot 200 then let set for 20 min no start) THANK YOU so much for all you help and thoughts. In these tough times any little info to save some $ is.. well... just awsome.

The EGR tubes are on the drivers side rear right behind the throttle body. You will see a tube come out of the rear manifold, then go in to the lower intake manifold.

A vacuum leak can do strange things. So lets get that problem fixed before we start throwing any parts at your car.

Right on I will get on it as soon as I get home from work tomorrow. Can you buy the vaccum line and fittings at a local parts store? Thanks Again.... I hope I make it to work... If not I will have a "Car Sick" Day. LOL

Ya, just get a package of generic vacuum lines, you get get red, blue, and black. Then just cut them to what ever length you need.