Well, the car is running well now, so let me summarize what happened.

The spark plugs were messed up. My friend found a YouTube video in which a mechanic said: to test if you have leaks from anti-freeze onto the plugs, drain the radiator, and let everything dry out. If it then starts up (and only ...

Can somebody please name a specific scan tool that works with the 1995 Bonneville? I looked at several, and the salesman said that he did not think they were compatible.

Is there some specific make and model of a scan tool that DOES work with the '95 Bonneville?

We pulled out two of the spark plugs, and they look pretty awful. They have heavy carbon deposits all over the tip of the plug.

They are NGK V-Power, which are recommended for the Bonneville, and have run 19,000 miles.

Obviously the first step will be to replace them. Is it a sign that something ...

Thanks to everyone replying.

I appreciate the suggestion to look at the VATS. I tried a different ignition key, same result. Also the "security" light does not come on during cranking. I believe this eliminates the VATS?

We disconnected the MAF, but it made no difference.

The oil looks normal, as ...

I have had my 1995 Bonneville SE for more than a year, and it has been running superbly. It has 143,000 miles, and I put on about 20,000 of that.

A week ago I drove it for about 45 minutes from home, absolutely no problems. I stopped about a half-hour in a store, then on coming out discovered that ...

Low coolant it is. The difficulty is to know which pressure reading is significant, because it keeps changing. As you add coolant when the A/C is on (which is how you're supposed to do it), the clutch is going in/out. And the pressure goes down when the compressor kicks in, not up. I added about 1 1 ...

My 1995 Bonneville SE has 136,000 miles, runs quite well. However, the A/C works only marginally. It works best at Bi-level, the two higher settings don't seem to work.

If you watch the compressor & clutch while it's running, you can see the compressor clutch kicking in/out, in/out continuously ...

Thanks, Randall. You very likely are correct about this. I noticed that, just recently, the level in the fuel gauge varies much more than it used to. As I drive around, it might be as high as 1/2, settle down around 1/4, then drop to almost zero, and stall. Going up and down hills is a problem for ...

Rachael, beware of fuel starvation and stalling issues on hard cornering/turning when you have 1/3 of a tank remaining or less.
1992 fuel tank baffles were very inadequate. You want a tank from 95 or newer to solve the problem. This is a known issue.

I'd like some more information on this ...