Intake manifold noise
 

1999 S80 2.9

Just changed O2 sensors and reset fuel trim and cleaned the throttle body less thana month ago. I am currently experiencing a "clicking" or "tapping noise" that seems to be coming from the intake manifold area. Car revs harder than usual on cold start (used to rev up to about 1500 and now does it to 2000 and settles down to 1000 instead of 500-700 until it warms up and then it drops down to 500). Is this a vacuum hose/gasket leak in my intake manifold? Failing ETM? Piston slap? Or something far worse?

Thanks.

Check the intake plumbing under the throttle body. Clicking noise is typically your injectors.

Throwing a CEL or any codes?

No codes. Just really noisy. Fuel injectors are pretty new. I'll check the plumbing around throttle body.

On way home Check Engine light came back on. Now throwing codes p0141 and p0161. All four sensor are brand new. Will clearing them with ElmScan OBD not do the trick or could my Cat be bad on top of everything else? This car is going to kill me....

Plumbing for throttle body appears to be in working order.

p0141 Rear heated oxygen sensor (HO2S), preheating Faulty signal. Permanent fault

p0161 Rear heated oxygen sensor (HO2S) preheating, bank 2 Faulty signal. Permanent fault

Brand new sensors. Installed this weekend. What else could cause it to throw this code?

What did you do to "reset fuel trim"?

Unplugged battery after clearing codes. Is there something else?

How many miles on this vehicle?

176k. Right out of school. Need it to last a little longer. If it is just the Cat I will live with it. No emission tests here.

Curious about the timing... VVT specifically.

What do you want to know?

Any timing belt work or anything going on with the VVT? If you are hearing clacking/tapping and you are throwing o2 codes, and you've got some rev issues you may have something going on with a valve... don't mean to alarm...

How many miles on the current timing belt?

Can you do a compression test?

Pulled a CVVT solenoid code once but it went away and hasn't been back. Not sure about the miles on the timing belt. There is no sticker for work done but the mechanic thought the belt was in good shape. I was afraid it might be a stuck valve lifter or something of the sort.

I truly do appreciate your help, 75.

By rough approximation, to me, it could be related to the issue... timing, exhaust gases, etc.

It kind fo sounds like this engine:

http://www.youtube.com/watch?v=pxRx31f6BXQ

I guess it sould be a coil or wiring. The coils are all fairly new.

No worries, that's what we're here for!

If you had a coil or wiring issue you'd throw a CEL and pull a misfire on the OBD...

If not coil, and more timing/fuel mapping, you could possibly get that noise.

How's the tension on the timing belt?