About 2 months ago my 99 EM1 started to do some weird things randomly. Most noticeably was this. If I was driving and would let off gas and start to brake to slow down, it would make slight popping noises out of the back of the exhaust, like a backfire. Typically happens in 3rd or 4th gear around 3k rpm. Wouldn't happen often. Then about 2 weeks ago my idol started to randomly drop to 200-300 rpms, and then would come back. Today my car threw a p0133 code, O2 sensor code and died twice while driving from the rpms dropping to 0 during idol. I have DC Heads, and 2 1/4 inch full exhaust. did a plugs, wires, distributor, injectors, map sensor, o2 sensor, and fuel filter about 3 years ago, have about 40k on them and 136k miles on car. My thoughts were an exhaust leak but I was unable to find out, any suggestions? Thanks!

 

Does unplugging the O2 sensor make the engine run better?

 

 

Going to unplug today and see, is that likely that it would have gone bad that fast? Do they go out faster due to the exhaust and heads?

 

Unplugged the main sensor and it continues to do the same thing.

 

Hey hopefully someone can help me out...I have a "D15Y5" Block...with a
P2J-3 "98" on my head...can someone explain to me what head is on the block...if they belong together?...It's a 94 DX shell with the motor listed above in it....Thanks

 

I also have a 99 em1 with the exact same issues and would love to know what's causing this... Conducted all of the same tests, checked resistances, checked exhaust, full tune up, cleaned injectors (removed and in tank cleaners), new o2 sensors. Hopefully one of the gurus can chime in on this.... I just can't find the issue :/