Question about Pontiac Bonneville
This sounds like 1 of 2 possible problems.
a bad headgasket or a clogged catalytic convertor. i would lean more towards the convertor
Posted on Jul 16, 2008
Make sure that there are no obvious small diameter hoses that are torn or collapsed. look at the pcv valve area because of oil saturation and especially at the map sensor to make sure it is both plugged in and that the hose or mounting point at the intake is not at fault.... vacuum leaks cause lean codes and hesitation...
more hazardous to your engine is pinging and heating issues which could cause damage to the catalyst... could get expensive once the o2 sensors and cat go bad...
only other guess i can offer is fuel pump not putting out enough pressure but i would suspect a vacuum leak because of the hissing and symptoms you have described
Posted on Jul 28, 2012
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
Tips for a great answer:
Sep 15, 2013 | Cars & Trucks
on Jul 31, 2010 | Acura Integra Cars & Trucks
Sep 11, 2011 | 1999 Mercury Grand Marquis
Jan 09, 2011 | 2003 Honda CR-V
Apr 14, 2010 | 1993 Chevrolet Lumina
Oct 23, 2009 | 1997 Buick LeSabre
Jun 21, 2009 | 1999 Ford Expedition
Apr 14, 2009 | 2004 Ford Explorer
Dec 20, 2008 | 1999 Chevrolet Silverado 1500
1,437 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: