I first had the p0300 and it came on at high speeds and had hard take offs. The engine light would sometimes come on when parked idling. The spark plugs were done about 2 years ago. So I replaced the distributor and rotor and that didn't get rid of the code. I then took it to get checked out at one mechanic and he diagnosed the spider injectors. When I got it back from him it was idling really rough and really bad, worse than when I had brought it in. So I had the injectors replaced by another mechanic and it starts up correctly now, but it still has a rough idle. I pulled new engine codes and this is what i got from PepBoys:

P0300 - Random Misfire
P0135 - EGR
P1406 - O2 Sensor

When I search on the site:
P0300 - Random Misfire
P0135 - 02 Sensor
P1406 - EGR

The car will start up but idles rough the exhaust moves pretty violently and either sounds like it wants to stall out or the engine will race. I cleaned out the EGR valve but that didnt not help too much. Should I buy a new EGR valve? Or should I go back to step number 1 and check the spark plug wires, spark plugs etc.

Thanks for any input
-Steve

 

P0300 - Random/Multiple Cylinder Misfire Detected
P0135 - HO2S Heater Circuit Bank 1 Sensor 1
P1406 - EGR Valve Pintle Position Circuit

The O2 sensor being bad can certainly cause a lot of problems. To trouble shoot the problem with the O2 sensor, I would remove both upstream sensors (the ones between the exhaust manifold on the engine and the "Y" in the y-pipe) and switch sides. B1S1 is the driver side and B2S1 is the passenger side. If the code changes indicating a heater issue with the B2S1 sensor, then the sensor is likely bad. If it does not change, then there is a problem somewhere else.

For the EGR code, I would strongly suggest removing the EGR valve, cleaning it, and reinstalling it with a new gasket. Be sure to get the gasket that has the integrated screen.

 

I removed the EGR valve and cleaned it.....I am going to clean it better this time. As for the gasket does any local place have it....I asked at pep boys but they did not have it. I see rock auto does.

When I remove the sensors and the code on the O2 sensor changes to a heater issue will it run smoother?

Thanks for the help.

 

Swapping sensors is a diagnostic step. The current code is for the heater circuit for the sensor. If it changes sides, then you know the sensor is bad, that is all. Give it a try.