99 Grand Prix GT with some problems

I have a 99 Grand Prix GT (3800). About 400 miles ago my car was running great, when i stopped at a stop sign and it died. It started back but ran really bad. I had it towed in and they said it was the catalytic converter. I just had it cut off and a piece of pipe put back. It has a distinct exhaust note now, but i dont mind it. I took it on a trip a week later and it done fine until i was coming back. I left a stop sign and white smoke was everywhere but it never got hot. I pulled off and the car died and would not restart. I had it towed and they said it was the plenum. $550 and 2 days later i got to come back home. Now the car seems to run okay but now the check engine light is on. If this was caused by the converter i would have thought it would have been on 400 miles ago. Just like to hear if anyone else is having similar problems or just me. Let me know what is coming next.

Go to Autozone and find out what the code is. They should be able to scan it for free. You'll be able to combat this problem more once you find out what code the car is throwing.

Maybe the clogged cat messed up the o2 sensor?? Usually when people remove the cat they use a o2 spoof to fool the sensor. If there is no spoof then usually it will throw a code.

All GM cars and trucks built after 1996 are called OBD2 which basicly means that a check engine light will not come on until certain enable criteria are met. It is possible to go weeks before a SES light comes on.

The PCM does monitor converter operation to see how good of a job it is doing. Removing your converter would cause your SES light to come on. I would bet you have a P0420 code stored in the PCM. Removing the convertor would effect your fuel economy and some other things. Most states it is illegal to remove the convertor.

When a convertor goes bad they don't just go bad something made them fail, a tech has to find the reason for the failure and not just change the convertor.

the check engine light was from the catalytic convertor being gone. about a week later the wheel bearing went bad on the front. $168 just for parts. it has a hub bearing. about a year ago the blower control module went bad and the ac/heater would only work on high. when they go out it, first it is just the first setting and they burn out one at a time. now i have 3 settings left so i get to tear the dash apart again. my 93 ranger with 165k on it gives me no problems. my low mileage grand prix is a POS so far. the trade in value is terrible on and car so i have to say i have bought my last car and my last GM anything. i wouldnt recommend a POS Grand Prix to anyone. nothing but junk when it comes to cars.

Go to Autozone and find out what the code is. They should be able to scan it for free. You'll be able to combat this problem more once you find out what code the car is throwing.

Maybe the clogged cat messed up the o2 sensor?? Usually when people remove the cat they use a o2 spoof to fool the sensor. If there is no spoof then usually it will throw a code.

I recently replaced my converter with a high flow and it is throwing the SES light and I need a emmissions test soon. Is there a way to fix the SES light with a sensor bung and can it be installed after the fact?? I had the converter welded on. I have a 2001 GP 3.8 litre.

Thanks!

99silverGT, the convertor should never have been removed in the first place so I wouldn't blame the car for that problem. The fan motor can be repaired by changing the fan resistor that is mounted under the dash next to the heater motor. It is a $40 part. As far as the wheel bearing is concerned they can go bad anytime. I had one go at 40K miles on a Grand AM. You just have a few minor issues to deal with. Once you get them corrected I believe you will have a great car!

There is no hesitation or performance loss, car runs fine. I just would like to know how to get the SES light off, I heard you can install a 02 sensor bung and that should fix the problem.
Next thing would be to go back to OEM new but I don't want to do that

I have a 99 grand Prix and I took the converter off.. But I knew it had a o2 sensor before and after the converter and removing the converter would cause the service engine light to come on.. So I ordered an o2 sim from lmperformance. It takes the place of the o2 sensor after the converter.. Go to this web site and it will tell you everything about it.
http://www.lmperformance.com/2983/12.html

Taking the converter off and putting a o2 sim (simulator) in place of the o2 sensor will give you the same if not better gas mileage. And it will increase the horsepower and performance of your car.

http://www.pfyc.com/store/merchant.mv?Screen=PROD&Store_Code=PFYC&Product_Code=WB5007&Product_Count=8&Category_Code=GPEXH

So I just plug it in and it should throw the SES light off???

So I just plug it in and it should throw the SES light off???



It might go off and it might not.. Because that car has a OBD2 (Computer). Once the OBD2 throws any code the only way you can clear it is to take it to AutoZone of a shop that has a code reader and they can clear it...

If you plug the 02 Sim in and the SES light is ON take it to AutoZone and they can turn it off in like 2 min.. The SES light will not come back on unless there are other problems..

If you plug the o2 Sim in and the SES light is OFF you will be ok. But i would recommend you to still have the o2 Sensor code cleared. Because once the OBD2 throws a code even if the SES light goes off after you fixing the problem it will still be in the OBD2 memory.. This will not hurt anything but it is best that you keep the OBD2 memory cleared.

So I just plug it in and it should throw the SES light off???
Thanks for the advice, I took it to auto Zone and they deleted out the code for me.