Slight Miss at idle.. replaced the normal stuff

[sreidmx]

Hi Guys,
I am new here, I have a 90 325IS that is in pretty good shape, 204k on the clock. We have been working a lot on it lately and I only have a minor suspicion this is even a real issue.
I have replaced all the vacuum hoses on the intake, I rebuilt the injectors and verified they are spraying properly and not clogged. Adjusted the valves, double checked the throttle sensor, I need to look again because I didn't use a feeler gauge.
Compression tests come back pretty dang good, all within range but good for a 200k motor.
New fuel filter and FPR, cap/rotor, plugs..

O2 has not been replaced for a while?? might be it.
and the head-gasket was done a few years ago.. not many miles since, also the timing belt was done too at the same time.

It runs great actually, pulls hard to rev limiter smooth etc.. just has a little miss at idle.. I really dont care about it too much except I am smogging it Friday.. Now the car sat for a while and the battery went dead, I am going to drive it as much as I can before friday to try and get the fuel trims set. Is there anything else I should look at before hand?

Thanks -Steve

[dnguyen1963]

O2 has 100k change interval. If your has not been changed then it is time to do it. You must have a parasitic draw if your battery went dead while the car sits. Change the O2 sensor before smog test is my recommendation.

[sreidmx]

I'll do that. Any recommendations on brand? Or just the Oem Bosch

[dnguyen1963]

Stay with OEM.

[Old525i]

I am interested in your smog results.

[sreidmx]

Ok so here are the results, I tested the tps just to be sure and it was spot on, changed the oil got rid of vaccum leaks that I missed, actually there was 4, the hoses from the valve cover to the Tb the hose from the iac were also leaking, so band clamps fixed those.. I checked the O2 and that didn't change anything, also reset the ecu.. That didn't fix it either, I checked the manual and it described the dependent sensors, temp switch, temp sensor and o2 are tied together. Since it ran good otherwise and I didn't know where else to look I replaced both. That helped significantly. I ended up doing it this morning.. Of course i did... Ended up running around to different shops because they didn't have the equipment to test it. Finally found a shop that was star certified.. Which I didn't need but said what the heck. I passed by 2 hydrocarbons... Literally the max is 108 and it showed 106!! So needless to say I am glad I replaced those sensors.