background: 357 le1 heads, cc306 cam, longtubes, ported intake, 30lb injectors, 3000 stall, 4.10 gear, 58mm throttle body, cold air intake, fuel pump, ewp.....after all this was installed i got a mail order tune from madz28. when i first take the car out it drives normal with no problems. after about 2 min of driving the car develops what seems to be a miss fire because it studders and shakes all the way up to 3000 rpm then goes away. if i put the throttle at half way and drive away it studders until that 3000 rpm mark and then just takes off like a bat outta hell without me pressing on the gas anymore than i was. what would cause this to happen only after driving it for a couple minutes.....why would it only be at the low rpm?

Bryan

 

Please get some diagnostic software and run it again. This is by far the best way to diagnose. I use DataMaster.

 

i'm not looking to spend more money on a labtop and computer software. there has to be other ways to figure this out than that

 

nobody has any opinions on what it could be?

 

this just happened on my new motor and i scanned for codes and came up with dtc16 which is low res output failure in the opti. I went ahead and replaced the opti, icm, coil, and wires and it runs great now. Im sure it wasnt necessary to change all of that but i just wanted those parts to be new since everything else on the motor is new.

Look up the icm spacing mod on shoebox's site because maybe your icm is getting too hot and malfunctioning? Maybe not, but its free to try.

 

ya, i guess for free its worth a try....thanks

 

so i have not been able to do the spacing mod yet, but i took it around the block today and from start up to goin around the block it was fine, but when i pulled back in the driveway, the check engine light came on and the fans kicked on immediately. but my temp was still low at around 160. what could be causing this, once the check engine light comes on the car runs like crap, and even sfter the light goes back off it runs bad, like its tryign to compensate for something??????

 

The fans will come on along with many different codes by default. You NEED to get the ses light checked out if you want to figure out whats wrong with the car. It could be the opti but you dont want to put 300 into an opti and that not be the problem. Or the icm. It could even be the coolant temp sensor in the water pump. No sense in throwing money somewhere and not fixing the problem. Get it scanned!!