Hi to all,
I am new to this site and need some help. I have a 96 LT1 with an Lt4 hot cam. I have a problem with the rpms surging at part throttle and the idle is ruff. I have no codes and have done the following. Replaced the iac, tps, map, icm, cts, plugs wires, coil, egr and solenoid and swopped the opti with a known working unit. I have checked the wiring and connections and everything was good. No vacuum leaks and my fuel pressure is at 38 with regulator connected and 45 with out. The regulator is not leaking, and I did drive aroung town with a gauge connected and the pressure stays with in range. Out of all of the things I did the spark plugs helped the most so I thought it had to be the opti. Replaced it and the car ran great for about 50 miles and now it’s worse then before. This motor has 10k miles and was installed in the car about 2 months ago. The computer was programmed by PCM for less. When the engine is acting up it almost feels like you’re hitting bumps. It also has a lack of power. Any help would be great! Thanks in advance.

 

Have you replaced the plug wires?

 

Yes the wires are new from Auto Zone. I went cheap with the wires

 

what kind of opti did u get? rebuilds are not known for longtivity or quality.

 

One from a running L99

 

my first response would be the used opti bit the big one. i just had a 5 month old msd opti bite it. luckily sumit is taking it back and refunding so im using a gm/acdelco performance this time.

 

When yours went did the engine run?

 

yah but gradually got worse till it idles really bad but touch the gas it dies let it idle it dies. should have the new opti tomorrow or the day after. ill let u know how it goes if u like. only code im getting is 51 prom error. pcmforless says its most likely the opti.

 

You did not mention the ignition coil module. Before going for another opti, you may want to check it out. It is a lot cheaper than a new opti.

 

Thanks, Mine never stalls but it stumbles bad from 1,200-2,000 rpm. The strange thing is I don't see a change in the rpms but I feel it. I tried 2 icm and no change.