1987 Crown Vic 5.0. Just bought it from my dad. It hasn't had to have an
emissions test in 8 years or so. Where I live, it has to pass. I half
expected it to fail because it had a slight miss under light throttle. I
only ran it thru the test because I really wanted to hurry and get it
licenced. It failed yesterday on 2 counts:
CO at 15mph was double the limit. CO at 25mph was under the limit barely.
HC at 15mph failed. Limit is 55ppm; I had 130something. At 25 the limit is
100, I had 140something.
I took the car home and changed the Cap, Rotor, Plugs and Wires, and Air
filter. The plugs, wires, cap and rotor were all the original ones. 21
years and 104k miles. The gap was supposed to be .48, but was close to .80
on all plugs. The number #8 plug was so ashed up that the gap was nearly
The miss was almost completely gone afterwards, and I was very happy. Took
it today to get reinspected and it failed again.
This time the CO number at 15 mph was .19, just under the limit of .22. So
that was improved. Unfortunately, the HC was actually WORSE! Both the
15mph and 25mph numbers were slightly up from the day before, which I don't
at all understand.
Today I pulled the KOEO codes and got a 34 and a 67. The 34 is an EGR
error, but from my research, it doesn't appear that it should affect the HC
numbers. I'll fix it obviously, but I don't think it's going to solve the
The only think I know of that might cause weak spark or incomplete ignition
is that the coil terminal pin was corroded, but I tried to clean it up a
little bit before putting the new wire on. Maybe that's it, but I seriously
The only other thing I can think of is that I noticed a few years ago that
the thing doesn't like 87 octane gas. It will ping on it sometimes. In
fact, I had to pull a long hill on the interstate last year and I thot it
would knock itself to death. That's probably the EGR problem, but I wonder
if the timing could be off enough to cause that and the HC problem.
My plan at this point is to take the intake manifold off, which needs a new
gasket. While I have access to everything, I'm going to replace the PCV
screen, grommet, valve and hose. I'll have access to be able to see,
inspect and replace, as necessary, all the vacuum hoses. I'm going to clean
the plenum, take off the EGR and clean it and the ports.
Okay, what next? I'm so irritated.