power loss engine light

**2002blackz28** · 06-24-2009, 07:38 PM

I have a 2002 z28 with A4 with 70,000 miles completly stock. I just bought the car 1 week ago .The first week i drove it it was real strong threw out all of the rpm range .I mean as the rpm picked up threw 1st gear I could really feel the torque and pulled really hard. Then one day the engine light came on and threw a o2 code started running rough . Ive had it replaced and It now idles and runs fine. But it's not what it was before as far as pulling hard threw out first and the power bands. It's just seem that the power would be like it was before. I also cleaned the MAF and new air filter. I have run the car hard several times now but like I stated above seems a little slower. Its been hotter outside latley than normal about mid 90 degrees than when it was running like a raped ape .Maybe making engine a little sluggish
Also no engine lights comming on and I replaced fuel filter and changed all fluids. I thank everyone in advance for help

**FORD RECOVERY EXPERT** · 06-24-2009, 09:07 PM

Originally Posted by 2002blackz28

threw a o2 code started running rough . Ive had it replaced and It now idles and runs fine.

Which sensor was it?

**karpetcm** · 06-24-2009, 09:41 PM

1st things that come to mind would be because your 02's failed it will cause your cats to fail, what i mean is it could easily damage them. If that happens and you ran rich for example the cats would just be clogged up or lean it would also damage them. If your car is idling fine and running good just a bit low on power, im steering away from plugs and wires but id check them anyway since youve already done a couple of other things.

**FORD RECOVERY EXPERT** · 06-25-2009, 08:04 AM

^ that was my thinking also... I was Wondering if it was a 'fore or aft' cat sensor that was bad...

**2002blackz28** · 06-25-2009, 08:15 AM

Originally Posted by FORD RECOVERY EXPERT

^ that was my thinking also... I was Wondering if it was a 'fore or aft' cat sensor that was bad...

I was the drivers side after the cat. Some times i do here noises sounding like a bad cat but the dealear checked them out and said they were good. Mabey I should go back and see if they will replace them. I will change my plugs and wires for now

**FORD RECOVERY EXPERT** · 06-25-2009, 08:26 AM

By good, did they mean they were in like new condition? or, that they would simply pass the sniff test?

They could be Going bad, But still in the acceptable range for emmisions.... What are the Emissions laws like where you live?

**2002blackz28** · 06-25-2009, 03:05 PM

I live in michigan ,No checks required and I guess I could delete them or go with somthing other. Also I've noticed that my interior lights and head lights flickering or pulsating . Could the electrical be the issue with the sluggish performance mabey causing low spark voltage. Ive heard threw other post that it could be a bad wire to or from the ALT. I've replaced the battery and the ALT tested good. But I could have a intermentant problem with a bad wire or connection. Thanks again for all you help and input to help me resolve my problem

**blue02Z** · 06-25-2009, 03:32 PM

after the cat o2 sensor wont make your car run rough, it is just a catalyst monitoring sensor.

**FORD RECOVERY EXPERT** · 06-25-2009, 04:11 PM

Originally Posted by 2002blackz28

I live in michigan ,No checks required and I guess I could delete them or go with somthing other. Also I've noticed that my interior lights and head lights flickering or pulsating . Could the electrical be the issue with the sluggish performance mabey causing low spark voltage. Ive heard threw other post that it could be a bad wire to or from the ALT. I've replaced the battery and the ALT tested good. But I could have a intermentant problem with a bad wire or connection. Thanks again for all you help and input to help me resolve my problem

This is also a very good possibility. (you neglected to mention this fine detail

)

Originally Posted by blue02Z

after the cat o2 sensor wont make your car run rough, it is just a catalyst monitoring sensor.

The sensor has been replaced, but a clogged cat, could be redsponsible for the failure, a clogged cat can generate EXTREME heat among other things, killing the sensor in the pipe nearby....

**2002blackz28** · 06-25-2009, 05:33 PM

sorry I meant bank 2 driver sid number 1 on the exhaust MF. I been a little confused latley

**2002blackz28** · 06-25-2009, 05:47 PM

Would a electrical issue with low spark voltage throw a code??
It seems to me that I would here a misfire. I just bought spark plugs OE . I will install this week end and hopefully have good news soon. I hope to get this fixed soon . I hate the idea of this car not running 100% because of a wire or a cat or sensor

**JaycenK** · 06-25-2009, 05:48 PM

Originally Posted by 2002blackz28

I live in michigan ,No checks required and I guess I could delete them or go with somthing other. Also I've noticed that my interior lights and head lights flickering or pulsating . Could the electrical be the issue with the sluggish performance mabey causing low spark voltage. Ive heard threw other post that it could be a bad wire to or from the ALT. I've replaced the battery and the ALT tested good. But I could have a intermentant problem with a bad wire or connection. Thanks again for all you help and input to help me resolve my problem

First off did they test the alt on the car or off?
Lights flickering and pulsing is the regulator in the alt. I had one I bought and had same problems at idel and took it back and they tested it and said it was good. We argued and argued and fianlly I just bought a damn regulator and put it in and problem solved. They wanted to say it was my ignition and everything else but in the end it was a 25 buck part that should have been covered by them.
Come to find out the machine they put the alt's on spins it at 1500 to 1800 rpm equiv. thats why it tested good because I only had the problem under 1300rpms.

**2002blackz28** · 06-25-2009, 06:04 PM

Is the regulator easy to install?

**2002blackz28** · 06-25-2009, 06:07 PM

They tested it on the car and had me turn on AC and lights. Do you think It would cause the car to not run to its full power during accelaration. seems like it may cause a misfire or 2. I will replace the regulator friday.

**karpetcm** · 06-25-2009, 08:40 PM

Well you can easily get your alternator checked for voltage and it is very important that its running properly because if its not your ECU will not work properly. If you had it checked then i dont think its a bad wire because if checked properly it will show voltage drop if it had a bad wire, did they check before and after alternator for voltage? with load meaning on the car. I still think you could have a cat issue and the dealer telling you there ok is i guess there opinion but im sure they didnt take your cat out and look inside of it and probably just moved it a bit to see if there is any rattles coming from it since that method doesnt exactly tell you how clogged your cat can be. There are way more knowledgable people here that can help you a bit better, GL either way

**FORD RECOVERY EXPERT** · 06-25-2009, 08:49 PM

Originally Posted by karpetcm

I still think you could have a cat issue and the dealer telling you there ok is i guess there opinion but im sure they didnt take your cat out and look inside of it and probably just moved it a bit to see if there is any rattles coming from it since that method doesnt exactly tell you how clogged your cat can be.

Not ruling out the voltage, But he'd be lucky to have gotten that, there are emmisions parameters that have to be maintained in order to be "Good". They prolly just hooked up the sniffer, and if it fell in the low end of acceptable, Its GOOD

....

**2002blackz28** · 06-25-2009, 09:48 PM

if its the cats .what replacement options do i have

**FORD RECOVERY EXPERT** · 06-25-2009, 09:50 PM

Should be a warranty deal.... if not, !cats FTW.

**2002blackz28** · 06-26-2009, 08:27 PM

Today I started changing spark pugs and wires I got all of the drivers side changed The only one that plug and wire on the passenger side that I got changed was the 1st one and the back 3 are still in. I jacked up the car and started to get ready to try and change the other 3 . It started to get dark out and i think I need a little info and tricks to get them changed. Any way I slid over to the drivers side and lighty hit the cat and it was making a little bit of a rattle sound unlike the passenger side which is has no sound coming from it will tapping on it.I unbolted it and confermed that it was coming from towards the bottom of the cat.I think this is my slight power loss issue.Would this cause my car to be aliitle sluggish and loss a little bit of my torque. If I take this issue to the dealer do you think they will replace it or give me the run around. I'm going to replace it regardless but I would like them to take it all the way off and hopefully they will pay for it if they can duplicate the rattle..Does any one no how much the dealer will charge if they don't fix for free . I really appreciate all the responses

**FORD RECOVERY EXPERT** · 06-26-2009, 09:31 PM

Well, a dealer cant ! the cats.... And replacing em there will be very expensive... So if they wont warranty them, take it to a local exhaust shop and !cats, then get it tuned. Prolly spend close to the same amount as replacing them.

EDIT: ! = delete