any

 

Have you tried replacing the two MAF relays?
There is a MAF power relay and a MAF burnoff relay both located on the firewall behind the battery.
I'd try that first.

 

Wow, that's crazy!
Very strange issues.

As far as an aftermarket security system goes:

I've had a Viper alarm in my car since '91 and it is interfaced with the factory alarm and VATS. It has all the sensors + extra sirens w/battery backup.
It will lock/unlock the doors while arming/disarming the factory alarm as well as the Viper the same time. It will also pop the hatchback from the remote.
I have issues with just the factory alarm because there are no glass breakage sensor, no jackup/tilt/towing sensor, no motion sensor. I wanted the factory alarm with all the extra protection of these extra sensors as well as secondary starter kill (kept the VATS also).
I've had zero problems with it since the original install except I had to replace one sensor (jackup/tilt/towing) that was mounted under the hood and the heat/humidity/age got to it.

I'd highly recommend a Viper with a GOOD professional installation.
I do my own mechanical/electrical on most everything in the car (aftermarket stereo/amp/DVD) but I left the alarm to the pros.
They know all the tricks/tips on each model car if you go to a good installer.

Just my 2 cents!

 

After market security systems are notorious for causing problems. Why do you need one? The car comes with a horn-honking security system, plus you need a key with a computer chip the start the car. What else do you need (besides theft insurance)?

 

I have issues with just the factory alarm because there are no glass breakage sensor, no jackup/tilt/towing/shock sensor, no motion sensor. I wanted the factory alarm with all the extra protection of these extra sensors as well as secondary starter kill (kept the VATS also). The sirens as well as alarm brain have battery backup also.

If someone is going to break the door glass to steal your targa top the factory alarm won't do anything.
Same issue if someone tries to jack up the car to steal your wheels. Nothing.
If you have all the sensors adjusted properly then you shouldn't have any issues with false alarms. Unless a close by clap of very loud thunder might set it off. If someone even kicks a tire hard it will go off. If I have the top off and someone sticks their hand inside the motion detector sensor will trigger.

Actually I'm getting ready to upgrade to the two way Viper alarm that has the LCD screen on the remote and the alarm sends a signal to your alarm remote in your pocket if there is an attempted (or actual) break in.

Even though I carry great full coverage insurance I'd rather have extra protection than not.
I've never had any issues with my aftermarket alarm.
I didn't go to any of the fast food installers like Best Buy or Circuit City either.
I had it done by an independent shop who took his time and made sure he soldered all the wires and adjusted the sensors properly.

To each his own.
I'm careful where I go and park and she's garage kept so I guess I'm just paranoid.