About a week ago, my TPI Fahrbirt (you know you've heard somebody pronouce it like that - Firbird if you're not from the south) started to have this mysterious "miss" when I'm launching. It has developed a couple hiccups when I turn it over cold, but otherwise runs exactly as it should. Launches fine, runs fine. Usually after a 30 minute or so drive, if I were to turn the car off and let it sit for 10 minutes or so, the trouble would surface upon restarting. This is a 5 speed car; if I were to launch normally (smoothly) it kind of cuts out, won't die, but it sounds REALLY choppy. I have to then clutch-in and rev him to about 3k (like how I used to drive a clutch before I learned the proper way). If I come to a complete stop or round any corners in 2nd, I have to really rev it up so I don't hit the chop.

Since this all began I have noticed it is getting terribly hot inside the car, with the windows rolled down, at night. The tran hump and shift lever are noticably hotter. The headers are not glowing, the exhaust is not glowing, the trans is full of fresh syn ATF. I replaced the plugs with some autolites I had taken out previously. Those were fine, not fouled, properly gapped. The Bosch 4-prong ones I removed had some carbon fouling on 6 of 8, with the other 2 having minor blackening on one side. I removed the cap and inspected it; inspected the rotor; I inspected the plug wires; the timing has not been changed (currently 6*); all looked to be in good shape.

I don't know whether it is worth noting, but the the block, heads, etc is all new, maybe 5k miles thus far. The 5.0 TPI rig and the like were transferred over. (1989 Formula) I wonder if any of the injectors may be going bad. Anywho, I don't know where to start looking next and would appreciate some direction.

If I can supply any more information, lemme know and I will. Thanks to all who reply.
Eric

 

I wish it wasn't a TPI but the problem is probably the same.

I've owned a 91 454SS pickup truck (TBI) for about 10 years now. I guess about 5 yeas ago, it developed a miss. Nothing bad, no lack of power, but when stopped at a light and idling, you could every now and then feel a miss. If you didn't know any better, you would think it was an ignition miss. I changed just about everything in the ignition and it still had that intermittent miss.

Finally I decided to buy some new injectors. I've never had that miss again after the new injectors were installed.

Not saying you're going to need 8 new injectors but it's possible.

 

I am thinking injectors too. But I'm also wondering how to explain the heat. Could this be a dying injector leaning out a cylinder or 2? I also deleted the AIR and made no compensation for it in the PROM, so could that be exascerbating the problem at all? Lastly, why would this only happen after a shutdown/restart?

 

Alright, I ohmed my injectors:

cold they were all 16.7-16.9
hot (immediately following a "miss") they were all 17.9 or 18.0

I guess my injectors are ok; so does anyone have any suggestions as to where I can go from here?

I don't know if it matters or not, but this all started the same night I swapped out the LS1 driveshaft and swapped back in the stock steel shaft.

Please dispense any advice you can....thanks
Eric