check engine light vacuum problem solved

[danielg]

This is a list of events leading to the solution of a 6 month cel problem.1. code showing failing oxygen sen2. replaced both sensors3. both failed4. Pontiac told to replace intake manifold gasket as a bad one can make sensors go bad5. Replaced gasket and still cel on 6. code said lean mixture and rear sensor slow7. found vacuum leak at bottom right of intake man with tell tale signs of black oily soot in a 6 inch area around it. Was told intake breaths in and out not just in or vacuum because computer is constantly adjusting flow.8. found a used intake manifold and problem solved, had to replace the the rear oxygen sen one last time.9. lesson learned vacuum problems can destroy oxygen sensors

[cptnsolo77]

Thx for posting!

[BlueCrush]

Great that you found out the problem. This should help out others on the site should they come across a similar issue.

[omgLIFT]

02 sensors can get pretty expensive to have to replace all the time. What was the exact C.E.L. code that you were running?

[danielg]

Sorry I can't remember the code pl151???? It translated to the mixture was too rich or vacuum leak. We found it by spraying brake cleaner on the intake hoses and manifold. Interesting enough my buddy mech who worked for dealers said the first clue was the soot around the leak as the intake manifold pulsates neg and pos pressure. Car is running great now and the miliage is amazing for the 1.8 fwd. Last year I got 55mpg driving from Jackson Hole Wym to Billings Mt through Yellowstone Park. A lot of 55mph and less but mountains and stop and go for animals on the road. Not to unusual to get 40mpg plus driving 55-60 and being easy on the gas.