Mods, CELs, and Engine Problems
 

Up until a week ago I had the following intake mods and exhaust:
CAI, ported plenum, ported intake manifold, and cat back exhaust.

I never tuned the car and I had no problems with the way the car operated after those installation. The car ran fine on the stock tune and I put almost 1,000 miles on the car without problems after installing those mods.

A week ago I put on long tube headers. After the installation, the car started up no problem and I drove the car home 30 miles from the shop where they were put on and I did not have any problems with the car on the way home either.

The next day after the LTH were installed, I got a CEL. The codes were P2096 - Post catalyst fuel trim system too lean bank 1 and P2098 - Post catalyst fuel trim system too lean bank 2. From some research on these forums it looks like a tune will solve these problems. I cleared the codes but the CEL eventually came on a couple miles down the road.

The CEL came back with the P2096 and P2098 codes and brought P0037 - HO2S heater control circuit low bank 1 sensor 2 and P0138 - O2 sensor circuit high voltage bank 1 sensor 2. I found a post where Rusty had a P0138 that he cleared by cleaning his MAF sensors. Not to discredit Rusty's experiences, I just think that might not be my problem since I never had the P0138 code after I installed CAI.

Eventually after driving it for a couple more days and about 50 more miles, the car started idling really rough. Yesterday, I turned off the car and when I came back to it a few hours later, it would not run. I would press the start button, the engine would briefly start and go into a rough, high idle and then die after a couple seconds. I tried clearing the computer by touching the battery cables together for a couple minutes and trying again. The same thing happened. The strange thing is that after the third or fourth try of me trying to start it, the engine wouldn't turn over at all. However, all of the electrical in the car would stay on (radio, nav screen, dash lights). The ignition indicator above the start button would say ON and there was no way for me to turn the ignition to OFF or ACC.

Have I gone one mod too far without a tune and will a tune even fix these problems? Has anyone encountered these problems with all these types of mods and figured out a fix that will let the car limp far enough to get me the tuner in a week?

Judging by the number of other members here who have installed LTHs and haven't had any problems after the install, I am sure whatever caused all these problems for me was self inflicted. But any help would be appreciated.

Sounds like a bad O2 sensor to me. Check sensors on right side of car. Your OBD reader may have O2s pre-configured; if not, they are standard PIDs.

I bet the shop who changed your LTHs used impact gun to remove the bolts and damaged your sensors. You need to replace the downstream sensors. Heater circuit/low or high voltage is common when sensors get exposed to excessive vibrations.

Would a bad O2 sensor prevent the car from starting?

Just out of curiosity, how much did the shop charge you for the header install?

$0. It was a friends and family discount.

I can say with confidence that there was no impact wrench used when we removed the sensors. Not saying the sensors aren't bad, just that an impact wrench wasn't the cause.

Do you still have cats?

The cats are not installed on the car any more.

Borescope.