My "Check Engine" light is driving me mad. I've been to 4 different shops, including a Dealer, and nobody has been able to permanently clear it.
I just bought a CarChip E/X at a local auto parts store. Pretty cool little device.
Anyway, I currently have two trouble codes...
P0402 - Exhaust Gas Recirculation Flow Excessive Detected P0304 - Cylinder 4 Misfire
These are actually the two codes that initially set off my Check Engine light back in October. I had a hell of time getting it to pass smog, but finally got passed two weeks ago... after blowing +$1700.
Here's the detail of the parts that have been replaced, in order:
1) EGR Solenoid 2) EGR Valve 3) Throttle Control Valve 4) A couple of cracked vacuum lines 5) O2 Sensor (upper one... not sure if there's a 2nd one) 6) Catalytic Converter (OBD II cat) 7) Spark Plug wires (I just did these today... they were due anyway.. will changed the spark plugs tonight/tomorrow)After getting items 1, 2 & 3 (above), the truck was failing smog with very high NO readings. My mechanic then changed out item 4, and ran a pre-test smog check. It passed with flying colors. Unfortunately, that shop couldn't run the real test because they cannot certify Gross Polluters, which mine was.
The very next morning, I ran the truck over to someone that can certify Gross Polluters... And it failed for high NO reading, again. This mechanic asked me to let him diagnose the problem and he would guarantee that he would find the problem and get it to pass. He told me that my Catalytic converter was history. So I let him install a new one. Sure enough, it passed smog... Finally :-).
3 days later the damned Check Engine light is back, the idle is very rough, and the truck is really sputtering at speeds under 20mph. Also, I'm getting horrendous gas mileage.So, anyone have any guesses on what's going on here? I still have $500-$600 dollars till I throw in the towel and head over to the Toyota dealer.