Problem: 197 a little bit 'laggy'

Hi guys.
Over the last few months I have felt that my 197 isn't quite as quick as it sould be.
My downstream O2 sensor failed when I first had the car so I replaced it with a Bosch universal sensor. The 'check emissions' warning has come on again and a diagnostics unit pointed the the O2 sensor again. I don't know which one, but I guess the universal sensor just didn't work out. Could this faulty secondary o2 sensor effect the cars performance?

I should note that since I changed the o2 sensor (all codes were cleared at this time), a 'missfire' code showed up on the diag.

Basically, the car seems to pull well enough in the high end of the rev range, but the lower revs are diabolical. For example, if I slow right down for a corner in 2nd, take the corner and plant it, there is SO much lag, easily 4 seconds of really slow building revs. Like turbo lag.

Last thing I will note that the only thing I haven't inspected in my ownership is the spark plugs. I have changed my oil and filter in the last 4k, replaced a dirty paper filter with a ktec panel filter and had all my belts changed.

Any ideas?

Help appreciated. I will remind you that to the untrained eye, the car would probably seem fine. I just know its not performing to it's full potential.
 
faulty o2 sensors can effect driveability - not a fan of "universal" sensors!

spark plugs are due every 36000 miles - if close to this i would just change them - easy and cheap to do

you can test the o2 sensor if you have "live" data on the diagnostic equipement - you can see the voltage from the sensor - if its slow to change its usually a good sign its faulty iirc not done it for ages ;/
 
faulty o2 sensors can effect driveability - not a fan of "universal" sensors!

spark plugs are due every 36000 miles - if close to this i would just change them - easy and cheap to do

you can test the o2 sensor if you have "live" data on the diagnostic equipement - you can see the voltage from the sensor - if its slow to change its usually a good sign its faulty iirc not done it for ages ;/

Re: o2 sensors, main dealer part only then you think?

My car has 44k or so now and I have nothing to back up that they have ever been changed. Do you know off hand what plugs they take?

Yeah, thats what I done the first time to conclude that the downstream sensor was gone. The voltage didn't move at all. I will try get that comp plugged in again to see if the new sensor has gone the same.

Would you have anything to say about the 'missfire' code?

Appreciate your input.

Aaron
 
dont forget, there is a flat spot upto about between 2-3k rpm, if you dont chance the gear right it also feels like lag.