2003 Buick Lesabre Misfire and Engine Light

Leave A Comment, Reply Or Ask A Question

4 Comments on "2003 Buick Lesabre Misfire and Engine Light"


The catalytic converter failed because it was running so bad. Check fuel pressure and check for a vacuum leak.


And lack of power before and after repairs when starting to step on the gas


I have a 2003 buick lesabre I am getting lean fuel code (p0171) and P0300 , I went to a shoppe they said it was misfiring because of lean fuel and catalytic was clogged. The cat would get glowing red. It also is running like crap, so I replaced the cat, intermediate pipe and muffler and both o2 sensors. I also replaced the plugs a week before this the plugs did not look bad. The 03 buick has lack of power when starting and is still running rough and getting codes,
I did disconnect the battery for 30 mins to reset the computer but still after new plugs, new cat, new o2 sensors, new intermidate pipe and new muffler Same codes p0300 and also p0171 but the p0171 after i erased code would sometimes come on but always the p0300 code. I also here a slight rattle when u slowly hit the gas. The rattle does not sound like a rod though it’s a more thumping type noise then stops

Any pointers??
Where could I look to find vacuum hoses diagram?
Could that be the issue?



Yes, sounds like to have a vacuum leak.