I had a '94 Firebird Formula that I pulled and rebuilt the engine. It could be either the Opti, MAF, IAC or the O2 sensors on the headers/manifolds. Maybe the computer, but I have not heard of the computer going it on them.
The LT1 is a tried and true iron block SBC that has been around for decades and is one of the best engines ever built IMO. It is one of the sensors, can be a pain in the ass to find the prob, but should be an easy fix.
Re-Reading your post, check the O2 sensors, sounds like your problem. The other things like A/C...no idea lol

[QUOTE=Avatard;399837]Yeah man, I'm afraid so. '87 5.0 GT. It needed paint, but it was all there One or two tiny rust spots on the hatch. Coulda been a classic in another model year. I think I'm more heartbroken than she was.

T-boned, at the left front fender, and the door. The A pillar took a good whack (good enough to crack the windshield), and the hit took out the upper ball joint, so it came home on wrecker. I had just gotten done dumping a shitload of new parts in it too; brakes, water pump, tires, it even had Flowmasters on it. Nice little Fox Body. Sniff.

I've been looking for maybe another shell to drop everything into...breaks my fucking heart, although I myself am responsible for sending my share of classics to the boneyard (but who knew back then?). If I knew some of those rusty old shitbuckets would be worth all that today, I'd have held on to them. Now you can buy replacement panels for fucking everything, and those old shitbuckets are worth more than I paid for my first house.[QUOTE=Avatard;399837]


Find a four cylinder and swap that stuff over! Or if you wanna make some money and are not in a hurry, part that Mustang out on Corral forum and get some of that back.


Here are a few in Jersey...
http://newjersey.craigslist.org/cto/1889637170.html

http://newjersey.craigslist.org/cto/1887533336.html

http://newjersey.craigslist.org/cto/1885024282.html

OK, so I decided to take the C4 out this evening. I had started it up, and for whatever reason, the intermittent clusterfuck issue was on hiatus. Or so I thought.

I go a few miles out to the Hess station, and fill 'er up with some fresh premium.

Should have never switched it off.

When it restarted, it was misfire city. I made it away from the pumps, and pulled over by the dumpster to fuck with it/wait for it to blow over/consider my next move.

My GF drives right past me, in her car. Didn't even see me, even though her headlights had to shine directly on my car, and she passed within 3.5 feet of me. I swear, this woman is sharp as a bowling ball (when I got home later I asked her if she heard a whistling sound in her head when the wind blew; fuck my life).

Mind you, as luck would have it, I left the house with no cell phone...so of course I was kinda screwed. I waited about 20 minutes, and it restarted running at least well enough to drive it (although it sounded like the Beverly Hillbillies truck), and limped home sputtering all the way.

The car gods are out to get me.

I need a new car, and a new GF...

Why would the code scanner not pick that up?

BTW, it seems to get worse when it gets hot. I let it cool a bit, and it restarts feeling much better.

It misfires so fucking bad that the cats start to smoke.

I'm so sorry man... I'm over here laughing my ass off right now. I'm truely sorry...

Something electrical is swelling with the heat and then contracting when it's cold. If it were older I'd swear it was the distributer cap (had a similar issue with an older car some years back). Check the electrics to feeding the spark plugs...

I would run the engine with the MAF sensor unplugged (has to be unplugged when ignition is OFF). Let the computer run off of speed density instead of air mass. If the misfire is never apparent, then replace the MAF sensor (they are notorously junk). If it still misfires, then look into the optical spark system, though they usually only fail if they get wet. My 93 Firebird with a 5.7 used to act up (misfire) on occasion come to find out it was the opti spark getting wet.

In earlier years (pre OBD2) the oxygen sensors had a large amount of authority in which would actually make the engine misfire. After OBD2, the calibrations were such that at the 21% +/- fuel correction would set the code, but not cause the engine to miss. You can also unplug the O2 sensors and see if it still misfires.

Mine has the ODB2 connector, even though it's a '94 (it must be a late '94, as I think it come online mid-year)

How many pins is it?

Geez, I dunno...the standard D-shaped connector. Same one on my '99 Expedition...the standard ODB2

I was kinda shocked, and expecting to find the older connector, so it was a relief. I was smart enough to get the to-of-the-line Actron scanner with the complete kit, and ALL the cables, though, because I tend to be a magnet for older cars...

I haven't had the heart to drive it since...in fact, I don't think I'll take it out without someone riding alongside as "backup". When I do, though, I'll unplug the MAF as you suggested, and try it.