stephendiaz28

Hey guys I will try and make it as short as possible.
94z28 heads,cam,edel intake, scorpion 1.6 RR,58mmtb,cai,longtunes,xpipe, fuel pumpbooster(not the one that goes hooked up to the TPS), stainless steel fuel line relocation wrapped with DEI reflective wrap not the tape
New parts- ac delco ICM and coil ( I put thermal compound behind the sensor plus I have the whole icm and coil which is also new about 3inches off the head to avoid overheating)
all ground engine to chassis grounds are new and using 2 gauge

so what happens?
After driving for a while id say about an hour the car suddenly stumbles and dies. Wait 5- mins and starts up stumbling then rpms jump up and runs normal then does it again about 15 mins after.
Also if I hit a bump hard enough the car stumbles and dies put it in neutral while the car is rolling and starts right up perfect.
another issues is car runs rough under very very light throttle mostly during start up and warming up?

Ideas?

ahritchie

iTrader: (1)

Any codes? Honestly, sound like new opti time! Have fun!


Is Your Opti-Spark Failing?

LT1 owners have dealt with the Opti-Spark distributor for 22 years now, but there is still much confusion regarding the causes and symptoms of a failing unit. Tapping into the PCM with a scan tool is a good way to start, but sometimes no codes will be set. Before diving into the Opti-Spark, be sure to verify that your grounds are good and the coil and wires are not the source of the problem, as they are much easier to change.

Symptoms:

* Car suddenly dies and won't restart
* Starts but immediately dies
* Extended cranking to start
* Rough idle
* Sputtering
* Backfiring
* Trouble reaching higher rpm
* Black smoke from exhaust
* Poor performance with car warmed up
* Weak plug wire spark
* Codes 16, 36, and 42 may be set

Read more: http://www.gmhightechperformance.com...#ixzz2tpf4cX5H

stephendiaz28

I was thinking maybe opti- nope no codes i have thrown codes before here and there but once i put the icm no codes have ever come back. coil is also new. My grounds are good as i checked them and i have also done the wiggle test to all the sensors and car runs fine. like i said only after over an hour or more of driving ( Heat soaked) does it shut off then turns on after sitting for 5 mins. the shutting down while hitting a bump happens anytime.

93Euphoria

How old is the Opti? Did you replace it along with all the new top end build?

And what about the tune & fuel? Start there. Definitely need to be more clear & informative about your tune, who tuned it, and more about the set-up if you want better answers.

Key information that stuck out is:

1. if I hit a bump hard enough the car stumbles and dies-- Could be your fuel pump, fuel issue, computer

2. car runs rough under very very light throttle mostly during start up and warming up -- Check your vacuum, EGR Valve, and O2’s. Check everything over! All Air hoses, Fuel lines, Ignition wires, ect..

The tune information is key for online diags