Stumped - OBD !@#$

[louivilleco]

This is my second post to this board. The other was "P0135". I continue to battle with OBD. I recently replaced my cracked exhaust manifold (95, 2.7l). Since, I'm showing P0135. A week after I installed the manifold, went through and re-torqued everything/checked the gasket to make sure it was seated correctly. Re-set the ECM and was good for about 20 miles before the chk engine light came on again. Read the code - P0135 again, put a new Bosch 13104 O2Sensor in... I could barely get 50 mph out of my truck, surging, skipping, the worst it's ever run. I took it out and put the old O2Sensor back in (ran fine again) but left the codes in the ECM. This time I was showing PO135 AND P0125 (insufficient coolant temp). I put in a new thermostat and flushed the cooling system (due anyway). Light's back on (P0135) I'm having a hard time figuring this one out. Throttle position sensor maybe? Vacuum leak, Exhaust leak? I have no idea why a new O2Sensor caused my truck to run like $#%#, Autozone took it back no problems as defective since it was showing the same code as before but I really think there's something else going on that my lack of knowledge is keeping me from figuring out. The kicker is, in its present state my truck is running better than it has for 50k miles. Thank You.

[Brian R.]

It's possible you got the wrong type of sensor. Maybe you need an A/F ratio sensor instead of the HO2 sensor you were sold, or vice versa.

Get a good part number from Toyota with your VIN. Make sure you get the right part.

http://www.autoshop101.com/forms/h37.pdf

[louivilleco]

Whoa, thanks for the "light reading". I intend to pour through that tonight. Also just called the dealer, they do have the correct 02Sensor (A/F ratio sensor) for my truck based on the VIN. It's a bit salty at 151 (I'll shop around - they told me it was a "Toyota Part"), but I can't take the CEL anylonger. Thanks Again. I'll let you know what happens after I pop a new one in.

[OBATDDSD]

urdusa.com has them for the 95 2.7 for $89.99. each. Denso brand sensors. I burned a cat converter gasket when installed a LC header. My stock manifold was also cracked. I had the cat gasket misaligned. I pulled the same code P 135. How are you reseting the ecu? I have a 95 s/c 2.7 manual trans.

[louivilleco]

I've been pulling the negative battery terminal to reset the ECU. I didn't have to deal with the cat gasket since I put on a "stock" replacement manifold. Still haven't been able to bring myself to dump the $$ on the O2sensor yet. Probably order one today.

[OBATDDSD]

I don't know which codes but some just don't erase by disconnecting the battery. You need to erase it by the code reader. Try that first before buying a sensor. urdusa.com has the cheapest price I've seen for nippondenso 02 sensors.

[louivilleco]

Reset the code, went for a ride up in the mtns yesterday put about 150 miles on my truck... no chck eng light... yet. Keeping my fingers crossed, but think I'll get a P0135 soon and be forced to order the sensor. Hoping it's just my ECU "adjusting" to the new manifold.

[Brian R.]

Good luck