rough idle and clunk in rear suspension
 

Hello all..

I have a 2001 SLS. ive had it for a year and a half. I do most of work myself but have run into two problems that i can not figure out. First I have a very rough idle and a spark knock. the spark knock is only when engine is warm. It runs fine while driving but at a stop or when in park it bounces from 600-850rpm. the engine does not stop ever. The service engine soon light is on and i pulled the codes and there were 2. they were saying that bank 1 and bank 2 were running lean. checked the mass airflow and checked for vacuum leaks the best that i could. I have been reading that the crank sensors are a common problem but just looking for a bit of advice....

Second, I have a clunk in the rear. I have checked for play and wear marks through out rear suspension but have not found anything. I sounds like it is coming from drivers side. Me and my father looked at it for hours one day and came up empty. we both have done alot of work on cars in the past. the sound seems to come when i hit small bumps. i dont really hear it when i hit big bumps. it sounds like kinda a hollow clunk. I have checked strut mounts, brake hardware and have pryed on everything possible and found no play. also sounds stupid but if i kick the rear tire i can hear a similar nose. the reason i kicked it is that i had it jacked up and wanted to see if that would help duplicate thenoise. not because i was mad.haha if u need a better explination just ask and i will do my best.

I thank you for taking time to help.....

RE: rough idle and clunk in rear suspension
 

I suggest spark plugs for problem #1 and correct grade of fuel.

For #2, I saw a sway bar shackle break once on a Bonneville (similar chassis), it clunked over bumps since it would flex and hit the underside ofthe car. Once welded it in place it was fixed.

RE: rough idle and clunk in rear suspension
 

It seems I have a very similar clunk noise on passenger side of '02 Eldorado and was just wondering if you have discovered the source of your problem. I changed out rear shocks on mine to no avail.