Please bear with me, as this will be lengthy. I purchased a 2000 C5 Coupe, all Stock 1 year ago. The car had 20k miles on it. Today, 1 year later, I have 28k miles. 4 weeks ago, I installed a BBK Intake Manifold. After the installation, the car has run perfectly for the last 3 week Last week, I added the BBK 80 mm Throttle body as well. The car ran perfectly the next morning on the way to work. About 12 miles. When I tried to start the car at noon to go to lunch, (car had been sitting for 4 hours since 8 am), the engine cranked but ran awfully. Almost sounded like a lawn mower engine. Got all kinds of error codes and then the eventual "REDUCED ENGINE POWER" All codes pointed to the TPS (Throttle Position Sensor) I ended up getting the car towed home. $90 on a flatbed for 12 miles. Oh well. Anyway, after tinkering around for several days I figured out the following. When the car was cold, it would start fine and run great for 30 minutes. Then, as the car got hot, I would get an irratic idle. At a full stop, the rpm would bounce up and down between 600 and 800 rpm. Then, after another 10 minutes of driving, the same thing would happend at all rpm speeds. The car would surge about 200/300 rpm up and down. Once I shut the car off and tried to restart it (while it was hot) I would get the "REDUCED ENGINE POWER" message and P1120, P1220, AND P1516 error codes.

During all of my troubleshooting, I also found the battery to be bad and replaced it. I removed all of the ground connectors and cleaned out all of the corrosion. I even sanded the painted grounding studs down to bare metal. This actually fixed another issue I had. The dashboard lights and the headlights would flicker all the time. Now, with the new battery and the cleaned ground contacts, the flicker is gone. One issue solved!

So, today, I removed the BBK Throttle body and reinstalled the stock one. This immediately fixed the surge in the rpm issue and all of the P1120, P1220 AND P1516 errors went away. Drove the car, no issues.

But, of course, a new problem has reared it's ugly head. When accelerating, between 1500 and 2000 rpm, depending on what gear the car is in (4 speed auto), a loud clicking noise will come from the engine compartment. Sounds like a playing card in the spoke of a bicycle wheel. It also reminds me of older cars with carbs when the timing was too far advanced you would get this brr, brr, brr clicking type sound during acceleration. However, on the C5, I believe the timing is controlled by the CPU.

Anyway. The car seems to drive ok. During the clicking/brr noise, there does seem to be a litle power loss. I have floored the gas pedal and the car shoots off like a rocket. But at over 2000 rpm, that clicking/brr/brr noise occurs during acceleration all the time.

One more thing. When I changed the throttle body to the BBK one the first time last week, I forgot to plug the coolant port on the engine block that connects to the throttle body. Some coolant, about 8 to10 oz slowly leaked out and ran down the front of the engine block. Not sure if that could have damaged something or not.. I did top off the overflow tank with distilled water. Also, when in park, and I push the gas pedal, the engine squeals. It sounds like a V belt squeal. I checked the belts and they both seem ok. The tension idler pulley seems ok too and it seems to have plenty of tension.

Before I take the car to the local chevy dealer and pay through the nose, any ideas from anyone?

Thanks for your time!

 

Ok, finally figured out where the noise is coming from. Power Steering Pump Pulley.

I pulled the V-Belt off and then checked each pulley. When I got to the power steering pump, I found the pulley made a clicking noise and that it seems to be loose and it wobbles a little. Question is, can I replace just the pulley or should I replace the power steering pump as well?

Thanks!

 

I think you can just replace the pulley but you will need a pulley puller for that.

 

I would assume thepulley is pressed on, so, if the pulley is loose, then either the pulley, or the pump shaft, or evenboth, have some wear. I would guess, unless the pump shaft is damaged, you should be able to replace just the pulley. If there is any wear on the shaft though, I doubt the new pulley willtight either.

Are you sure the clicking is just coming from the pulley and not the pump?