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Q: Check Engine Light - Car hesitates to go faster on 2002 Chevrolet Impala

I purchased the Actron Computer scanner which it told me that Injector #5 was bad, so I went and replaced it with a new one. I am now getting 2 codes P0300 and P0404.

My car will drive no more than 30mph, but after it get's warmed up it will drive normal, well some what. Once it's warmed up I can get it to go over 50mph, but the car shakes and hesitates to go faster.

Has anyone encounter this issue? I am thinking it might be my catalyct converter, but I don't want to replace it if it doesnt need to be. PLEASE HELP ME.
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It sounds like you may have a restricted cat cat convertor. As you can see by the other notes it is not an uncommon problem. The excess exhaust back pressure can be read by removing the front O2 sensor and connecting a pressure guage using a special fitting. The exaust back pressure should not be more than 1.5psi at 1500 rpm with the transmission in park or netural. The excess back pressure can cause both the EGR and misfire fault codes to set.
Some customers of 2001-02 Chevrolet Impala, Monte Carlo; Pontiac Grand Prix; and Buick Regal model vehicles, equipped with a 3.4L (RPO LA1 - VIN E) or 3.8L (RPO L36 - VIN K) V6 engine, may experience a condition where the vehicle exhaust catalytic converter is replaced due to complaints of lack of power or illumination of the Malfunction Indicator Lamp (MIL). This may be due to the front endcone insulation from the catalytic converter breaking away and blocking the front of the first catalyst brick and preventing the free flow of exhaust gas through the converter.
Special Policy Adjustment
This special policy covers the condition described above for a period of 10 years or 120,000 miles (190,000 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. Contact your GM dealer about this.
P0404 is a code for your "EGR Open Position Signal Range/Performance"
P0300 is a random misfire code.

You will need to perform some more diagnosis on the EGR valve. Is it stuck open? Has it failed?
We did not check the EGR Valve, but will do it today. It seems more to do with the cat converter. The car will not pick up speed anymore, it looses power.

It has an issue going past or getting near 2000 rpm's. I've only owned the car for a max of 3 yrs and I only have 86,700 miles. I do not qualify for the free instal. I did take my car in and was told that it is my cat converter. It runs a lot faster w/o it. Thank you both for the answers.
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