This just started about a month ago,and i've exhausted my knowledge and getting fed up.

It is a 96 gsr with a 99 b20b with a p8r head.It has a rough idle,died in traffic/lights,and has a hesitation between what seems too be 2k-4k and only when 1/2 throttle or less.Anything above 1/2 throttle and it doesn't seem too do it.

I've replaced...

Plugs
Wires
Distributor cap
Rotor button
Fuel filter
o2 sensor
Ecu (with a known to be good p75)
Tps
Map sensor


What else could this possibly be?

 

have you checked the codes?
you're probably gonna wanna run a tune with that p8r

 

No cel's.

It ran fine for near 2 years before this with just a p75.

Also,the miss seems to be getting worse.

 

Check your ground wires?

 

check valve lash. absolutely

 

ok this might seem weird but it worked for me. unplug ur downstream o2 sensor and see if that works. mine was doing the exact samething at those same rpms and i tried that and it hasnt done it to me anymore in about a month now. lmk wat happens.

 

Do it

 

do wat?

 

that really won't tell you much
and it certainly doesn't solve the problem

 

i was jus saying wat worked for me i know its weird but it worked.

 

So you basically had a faulty sensor

 

yea pretty much but that jus might not be the case for him. it may be stuck on limp mode also.

 

The hesitation is solved.It was a few different issues,one of which was the o2.


Idle is still funky though,raises/lowers ect.

Also,i've already cleaned/replaced the iacv.

 

yupp check ur tps or the map sensor.

 

no, it's not weird. and no, it didn't "work". all unplugging the o2 does is keep the pcm in open loop. that is, ignoring all pcm inputs. that just indicates that there is a problem with a pcm input or the pcm's interpretation of the input

it does not indicate a faulty o2 sensor. although, it doesn't cancel it out either

 

so how can i fix that problem. and i apologize not trying to thread jack

 

did you check the codes prior to disconnecting the o2?

 

not yet

 

if you want to make an attempt at solving this, clear the pcm memory, reconnect the o2 and drive it for a few days. then check the codes