I have a 1995 Trans Am LT1 that is stock except K&N filter, headers w/ dual cats, EGR block off and TB coolant bypassed.

The facts:
Car hesitates/surges during normal cruise speeds (while maintaining constant speed). Judging by the plugs on the drivers bank their is an intermittent miss.
Driver's side (cylinders 1,3,5,7) exhaust gets very very hot and blows less pressure than the pass side (2,4,6,8).
Compression is good on all cylinders.
No exhaust leaks - just replaced collector gaskets one of two cats and both mufflers.
No codes are displayed on the GM tech II scanner.

What I have replaced in the last three months (whether I though it would solve this or not):
Fuel Pump
Fuel Filter
Fuel injectors - stock rated Accel's
Coil with MSD - GM blaster
Optispark and vent lines
Plug wires to 8.8 mm Accel race wires
Spark plugs NGK TR55
Water Pump
O2 sensors
Drivers bank Catalytic converter (though it was plugged)
TB cleaned.
IAC replaced and releart.
TPS replaced
Unused vacuum ports replugged
PCV replaced.

The ECM seems to be richening the mixture according to the dealer.

Does the exhaust get very hot due to a miss/rich or lean condition?

What would cause this to only happen on the one bank?

Someone suggested one or two broken valve springs - would that cause a miss/lack of power?

Good and even compression suggests that valves and head gaskets etc. are O.K.?

Any suggestions would be appreciated since I have replaced almost everything on top of the block already...

 

I doubt it's valvesprings that are broken. If it was, whichever cyclinder(s) had the broken spring(s), then that cyclinder wouldn't hold compression because the valve would be open from the broken spring not being able to hold it up.

 

good luck I have the same problem and everyone points to the opti .If you find its something else tell me im going to get a delteq maybe that will work.

 

Thanks I will post solution if/when I find it.
As far as the opti goes both the old and the new one had the same problem (hot and weak driver's bank exhaust).
I am going to check the drivers side plugs tomorrow and will report which cylinder # plugs are fouled and try changing those wires/plugs again.
Should I try switching the injectors and / or injector plugs to the other bank to see if the problem switches sides?

 

i am having sorta that problem post results

 

Will post results.
Thanks Crazy 95Z - your logic on the valve springs sounds right on to me.

The only things I can think of that I didn't change was the map sensor (dealer swapped with another and no change) and the ignition module that the coil driver plugs into.

My logic / common sense points to something bank specfic however. I am going to try unplugging the drivers side O2 sensor tomorrow too and look for a change in exhaust temp (although I think the default is a rich setting anyways)

I never touched the knock sensors before - could a faulty driver's side one (ie. burnt by the header) have anything to do with this? (I would probably get a code though)

 

u would get a code with the O2s also i beleive. i am anyway and i am running very rich.

 

i was having a problem after my header install with one bank running extremely rich and fouling teh plugs causing a hesitaion making it undriveable

turned out to be one of my 02s put it back on teh tech 2 and check to c how the 02s milivolts are flucuating and check ur fuel curve

if ur 02s are flucutaion really fast they are good, if they are stuck or moving slowly they are bad,

i had no code when my 02 was bad , it just went

have teh fuel curve checked and c if one bank is pulling more fuel , if u switch 02s and the problem flip flops its an 02 problem

 

Problem solved.

I was lucky as it was simply a cracked insulator on plug #4 - when I pulled the wire off it broke. (I might have cracked it trying to tighten it around the header)

Driver's bang plugs all looked identically good while #4 was wet or the other bank.
Changed all plugs to new NGK TR55 platinums and the motor has never run so good.
Now both exhausts are the same temp and I'm not getting the glowing cat or hesitation and the power's back!

Unfortunately it may not help you other guys out but it shows that new plugs could possibly be faulty and to check the basics first.

The only code I got was a 24 (IAT) - replaced and code is gone.

Thanks again.