Greetings, and thank you in advance for reading and responding.

Having difficulty getting my 1990 Toyota Celica GT to pass the Utah
State Emissions test. I've had my emissions run 5 times with various
different failures. I only have the paper on my most recent failure to
provide what it last tested at. Done alot, and I'm just about at my
wits end.

When I first took it in, the test ran great except my hydrocarbon count
during idle were a little over double the allowable limit of 220.
Everything else passed well within acceptable limits.

My brother-in-law recently used a trick suggested to him by a mechanic
friend to get his car to pass emissions. He put 2 bottles of Heet gas
line antifreeze in his gas tank after a failed emissions test. His
subsequent test had a dramatic drop in the hydrocarbon count. Thought I
would try the same thing.

Put two bottles of Heet in my car. Next test the results flip flopped.
My car passed everything except for the hydrocarbon count at 2500 rpm.
The first time I had it tested, the count was somewhere around 80 with
220 being the limit. After adding the Heet additive, it jumped to about
800 hydrocarbons during rpm. Idle passed at about 140.

Ran another fuel additive through a full tank of gas. Refuled with
premium Chevron gasoline and had it retested. Back to the original
results. Hydrocarbons during idle were too high.

Replaced spark plugs with NGK platinum plugs. Replaced wires with a
Bosch premium wire set. Replaced distributor cap and rotor. Di-electric
grease was used on all contacts. Still failing due to high HC count
during idle.

Had an expensive fule system treatment done on my car. It failed last
year, and they ran this treatment and it brought it into line. HC count
went down, but still over the limit. This was the last test run. Here's
the results:

High Speed Test  -  RPM: 2392
HC - Standard: 220  Reading: 128
CO% - Standard: 1.20  Reading: 0.66
Co2% - Reading: 13.7

Idle Test  -  RPM: 741
HC - Standard: 220  Reading: 447
CO% - Standard: 1.20  Reading: 0.43
CO2% - Reading: 13.4

I've just replaced my O2 sensor last Friday evening. Disconnected the
positive battery terminal for about 40 minutes so that my ECU will go
into learning mode. My thought is that my fuel mixture is running too
rich during idle resulting in the high HC count. Haven't had it tested
yet, and I'm not sure if there really is much of anything else I can
do. The air filter in it is clean and was replaced about 3 months ago.
Had my oil changed about 3 weeks ago.

HELP...  I beg you!