Acceleration issue and unrelated/related noise.

**Speed Bump** · 06-17-2009, 01:40 PM

Any help would be greatly appreciated.

I am trying to figure out what is wrong with my 2000 Z28. (One owner) It is Automatic and All stock. It has not had any modifications. I have changed the plugs, Fuel filter, air filter. Scheduled oil changes every 3000 miles. Flushed and cleaned radiator twice.

Lets start with the noise issue and build up to the acceleration problem.

I have been hearing a noise from the engine area that sounds like a clatter. The only thing I can compare it to would be a rain stick. (hollow wood stick with beads in it) This noise started over a year ago but it could ONLY be heard when I was driving at about 30 mph and up. There is no noise when the car is in park. It can only be heard when it is in gear and moving. It is not constant or even consistent. It seems to be more apparent when the car is warmed up and when it is hot outside. Normal acceleration from a standing start is normal but if I let off the accelerator after it hits 30+ and I lightly apply the accelerator again the clatter appears. When I stomp it, It is very loud and it sounds like high speed metal hitting metal. (Loud rain stick effect) I have noticed some power loss across the entire power band. About 10% of the time it doesn't do it.

Changed the plugs (no visible scorching or damage to any of the plugs)

In the past few months I have been noticing the acceleration drop out on me about half way through each shift point. It drops about 500 RPM's for about a second or two every time and then resumes accelerating. This happens during slow acceleration and fast acceleration.

After this started I changed the fuel filter. (no noticeable blockage)

Recently I got in the car and started to leave the house and there was NO power what so ever. I had not driven it in two days. I could only get the car up to 10 mph. There was no excessive revving when I hit the gas and even when I floored it I could hear the RPM's start to build and then It dropped back down. The engine Quivered and hesitated as if it wanted to accelerate but couldn't.

I let it idle in the driveway for about 10 min and it seemed to idle normally. I reved the engine a few times and I could hear it start to choke out. It seemed to run somewhat normally and I took it to the auto parts store and asked them to see if there were any codes. They hooked it up and discovered that there were NO codes. After some discussion I decided to replace the Throttle Postilion Sensor. After changing the throttle positions sensor It was driving normally. I took it on a 400 mile trip and had no trouble out of it at all. There was still some hesitation halfway through the shift points and the strange clatter was still there.

I let it sit again for another two days and tried to leave again to discover the same problem. I couldn't get it over 10 MPH. I got it in the driveway and started reving it in small increments and I could tell that it did not want to rev but it did after some hesitation. I tried to drive it again and it just won't go over 10 or 15 mph now...

Does anyone have any Idea what may be going on with it? I greatly appreciate any input I can get. I have never had to work on it before and it all seems a little daunting. The last car I worked on was my 1990 RS. This thing is a space ship compared to it!

Sorry for the long read, I tried to be concise.

Thank you.

**FORD RECOVERY EXPERT** · 06-17-2009, 06:31 PM

First off, How many miles are on it?

**Speed Bump** · 06-17-2009, 06:33 PM

82,000

**FORD RECOVERY EXPERT** · 06-17-2009, 07:01 PM

Im gonna Start with Cat.... If its coming apart inside, that could account for the "Rain stick" noise.... and the lack of acceleration.... Any exhaust work ever done?

**Speed Bump** · 06-17-2009, 07:16 PM

Originally Posted by FORD RECOVERY EXPERT

Im gonna Start with Cat.... If its coming apart inside, that could account for the "Rain stick" noise.... and the lack of acceleration.... Any exhaust work ever done?

Nope it's all stock. I never thought about the cat... wouldn't the Post-Cat O2 sensor read a problem?

**FORD RECOVERY EXPERT** · 06-17-2009, 07:29 PM

Not neccesarily....

**Speed Bump** · 06-17-2009, 07:52 PM

Thank you for the information and the new direction. I'm going to pull them tomorrow and see what I have...

Thanks,

**FORD RECOVERY EXPERT** · 06-17-2009, 08:02 PM

No, problem.... Just let us know what you find.

**nillam1** · 06-17-2009, 11:27 PM

Originally Posted by Speed Bump

Thank you for the information and the new direction. I'm going to pull them tomorrow and see what I have...

Thanks,

Your cats have a warranty recall, did you know that before you take them apart? I think it applies to your car. Campaign - Catalytic Converter Warranty Extension
Subject:
Special Coverage Adjustment - Catalytic Converter Extended Warranty
# 05513 - (11/27/2006)

Models:
2000-02 CHEVROLET CAMARO
2000-02 PONTIAC FIREBIRD

EQUIPPED WITH 5.7L V8 (RPO LSI - VIN G) ENGINE

Condition

Some customers of 2000-02 Chevrolet Camaro and 2000-02 Pontiac Firebird model vehicles, equipped with a 5.7L V8 (RPO LSI - VIN G) engine, may experience a failure of the left or right catalytic converter.

Special Coverage Adjustment

This special coverage covers the condition described above for a period of 10 years or 120,000 miles (193,000 km), whichever occurs first, from the date the vehicle was originally placed in service, regardless of ownership. The repairs will be made at no charge to the customer.

For vehicles covered by Vehicle Service Contracts, all eligible claims with repair orders on or after November 27, 2006 are covered by this special coverage and must be submitted using the labor operation codes provided with this bulletin. Claims with repair orders prior to November 27, 2006 must be submitted to the Service Contract provider.
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