high idle in park

[jrod87]

MY 90 deville idles high in park then then start to make clanging noise from bottom of engine. please help

[caddydaddy]

Check the idle speed controller motor.

[jrod87]

the idle speed controller motor was unplugged and it fixed the idle problem but there still is a clanking sound from the bottom of the motor.

[caddydaddy]

Originally Posted by jrod87

the idle speed controller motor was unplugged and it fixed the idle problem but there still is a clanking sound from the bottom of the motor.

OK, so the idle speed motor is bad, that's a common problem as they get older. The clanking, can you describe that more? Is it just at idle, or when driving, etc?

[jrod87]

it clanks at idle and goes away when you take off. it sounds like its coming from the cat. It clanks in rythm with the engine.

[DFBonnett]

Try getting underneath and listen while hitting the cat, while cool of course, with the side of your fist or a rubber hammer. You shouldn't hear any rattle or clunking from inside the cat.

[D Spec D1]

It's probably the main bearing thump problem (harmless) or cold start piston slap (relatively harmless). My car has the latter problem, it sounds like the engine is about to explode for the first five or ten minutes, but if you drive it anywhere (even just down the street), it goes away, right?

[jrod87]

its not that loud its just a iritating clank you can't hear it from the top of the engine just the bottom and it starts when the engine is hot not cold. its weird

[maxwedge]

Bottom line here is, someone who knows what they are doing needs to listen to this noise!

[jrod87]

Took the car to a muffler shop, turns out it was the cat, thank you guys for all the help troubleshooting this noise.