Rough idle I have a 99 GMC Suburban I replaced the plugs,distribator cap,and roter button, and it is still running rough and now it gets a back fire when put into gear. I read codes says O2 sensor heater circuit malfunction (bank 2 sensor 1) Is this part of my problem?

well that firing order is wrong!
an Opel Kadett 200ie, 1996
no country told and 15 engines used world wide this car.
last one in UK is 1995
so I guess it is not UK?
sold under 11 names world wide.
IN UK it is really a Vauxhall Astra Mk II. badged as Opel. now that is confusing.
not diesel, but petrol AND ALL ARE INLINE 4 BANGER'S.
every car made ,every manual for for them in print tells you 2 answers ( distributors)
1: lost all distrib setting
2: or not lost SETTINGS, Crank not turned.

so read that book it tells you to do this.

SPIN ENGINE TO SEE DISTRIB ROTOR ROTATION CCW OR CW/? (HOLD THAT THOUGHT)
by hand
set crank pulley TO TDC ,-0 DEGREE'S AND BOTH VALVES CLOSED #1 CYLINDER. (CALLED FIRING)#1
CAP OFF. MARK ROTOR #1 TO DISTRIB BODY
THEN CAP ON AND MARK #1 ON CAP.
PUT #1 WIRE TO #1 CAP
AND 1,3,4,2, IN CW OR CCW DIRECTION SEEn ABOVE. at FIRST STEP.

DONE car runs.
if distributor was pulled there are 15 engine answers.

next time on all cars made on earth with HV spark wires
do them 1 at a time. and win.
distribs or any car with HV spark wires seen (sets)

Idle air control (IAC) control rpm idle during idle.

Test it on idle with ALL electrical on full force.
RPM should increase.
If RPM remain the same then IAC is question.

timing problem??

Check the idle air control on the throttle body it is on when the engine is first started stays on until the engine is warmed up.

need to check engine compression, possible you have a burnt valve, also double check your firing order on plug wires on dist. cap

Hi, I believe you hit the nail on the head. Black stuff in the filter Meaning that there is something in the tank. You have to drop the tank and clean it out. Good luck.

if i understand u correctly u replaced the distributor and cap if so i would start with making sure my pick up coil was installed correctlyand or replace it.i also would look at the possibility of it being a powertrain control module or neutral safety switch if this vehicle is equipt with one. hope ive been helpful

mcdevito75 here, Sounds like a faulty voltage regulator, it"s 1 unit with the alternator, change the alternator, also the alt. supplies juice to the ignition switch, distributor abd plugs, thus a rough idle due to bad alternator.

I had a 99 Suburban that did almost the same thing, it turned out to be the Catyletic Converters were plugged. Try taking the exhaust pipe loose at the manifold for test purposes. If it runs good with the pipes loose, that's the problem. Replace the Cat's. There were no codes for either, it would start and run nice for about 5 seconds, then run rough and then stall.

Maf or map sensor is bad or egr stuck open.