ok here is my dilemma, i rebuilt my LT1 to a 355 forged internals, cam is still the cc503 with 1.6RR, i used the old tune i had to just run the car then had a retune done by Pcm for less. two things i noticed it ran better with the old tune in it (idle, throttle response, overall driveability) but i noticed with both tunes the car runs funny after driving for a bit. it surges coming to a stop which it wont stall but is noticeable, but after being stopped at a light the take off it hesitates badly pops throught the exhaust then takes off again. this happens randomly sometimes worse then others and sometimes not at all. all the plug wires are fine, plugs are new, opti was replaced when i originally did my built (350 that the bottom end let go) 2 years now. so i am at a crossroad, i dont think its the tune because both PCM drive the same way and they are both tuned differently, i am thinking its more ignition related i just don't know where else to look. could it be that the RR were over tightned? or too loose? car acts fine after driving it hard or at normal speed but there is a noticeable hesitation just after taking off or say getting on the highway speed under load, but not noticeable driving along.
its very weird and i am at a loss trying to figure it out.

things i have tried:

checked all plugs/ wires/ connections (even in the dark)
checked egr if its working correctly (vacuum and connections)
checked around the intake for vacuum leaks

build specs:
355 forged pistons connecting rods
cc1.6RR with beehive springs
cc503 ls1 lifters harded pushrods
ported aluminum heads
block zero decked
48mm tb stock
water pump stock
opti is a gm unit
stock coil
msd ignition wires
30lbs SVO injectors
accel stubby spark plugs
pcm for less tune with vette knock module
cold air intake
CIA headers




anything else i should be looking at?

basics..

vac leak,
min air setting
map/vacuum lines cracked
fuel pressure
you need to log the data from idle to take off.

That thing got a MAF? If so unplug it and drive it to see if its still happens

^I will try that tonight

also anyone have good recommendations for datalogging software and/or cables for a 95 OBD1 for sale?

What brand spark plugs and gap?

ACCEL stubby @.050

Quick question, was your TB/IAC/TPS all reset correctly after? All 3 can/will cause surging and effect driving

If your not sure, best to reset them all, doesn't take long and will eliminate the possibility

reset procedure?

You should be able to load a copy of Freescan from here,I used it for my LT1

http://www.akmcables.com/dss.htm

Also Read this

http://www.pcmforless.com/index.php?opt ... &Itemid=89

Your welcome to my chord and laptop if you come grab it.

http://www.thirdgen.org/tpimod2

Might be the same for LT1's, but not 100% sure, only LT1 I did was a 96 ODBII so I skipped the paperclip and it still worked, please note though, the RPM's mensioned are for stock, idle on my 92 because of the cam/cubes was set to almost 1000 rpm or it would stall (throttle screw wasn't long enough so I had to set a peace of wood there to hold it in place once I found the sweet spot and plug'd the IAC back in, then removed to wood), with your cam your base idle may be around 700 to 800 rpm, but I am just guessing

Hope that helps

ya i will try that as well problem is not knowing what the IAC counts are on the car itself, i believe the idle is raise a little high as of right now but its also keeping it from stalling. i am doubtful that the TB would have anything to do with whats happening cause it sounding more and more like ignition related but heck i will try anything at this point lol

very well may not be the problem, but process of eliminiation, its easy to do and at least you know its set right after

Personaly, I'v had bad luck with your Accel plugs, had issues over the years with Bosch plugs too and NGK, I don't run anything but Delco's now, Usually there Rapid fires, had good luck with them

On our old 96 LT1, we had misfire problems under load that took for ever to solve, turned out to be the wires arcing out on the headers, found out by fluke changing the injectors and caught the car on fire, was an eventfull evening and a much longer story to tell, lol

i am not a big fan of my Accel plugs but the problem is clearence between header/ plug and wires i got none. Delco don't make a stubby plug that will work and the wires are just not taylored to my application.

i have had fire issues on my old car one night, lets just say 2 wires for the fan touching together do not work well, 4 hours later after the engine harness lit up like a firecracker and many many beers later we had the car running right again lol that was a heck of a long night.

Would a regular plug fit if you could use heat sleeves on the wires to protect them?