Any update?So! The nightmare continues. Fuel pump was replaced but we noticed the wiring harness was a little bit singed during replacement. We cleaned it up as best we could, buttoned it up, car was drivable albeit the miss was still obvious. Not more than a week later it died in front of the Chevy dealership here in town ironically enough. I had to walk 5 miles in the dark from the dealership back to my mother's house in the bitterly cold wind and rain. Good times!
Dealership looked at it, charged me $75 to tell me the fuel pump and distributor were bad. They wanted $1,800 to replace them both. I towed it from the dealership (another nightmare I won't go into) back to my mechanic, and we replaced the Opti (which ROYALLY pisses me off since the new one came with a cap & rotor that has to be used to protect the lifetime warranty it came with, so now the $200 MSD cap and rotor I bought in February lasted a whole 10 months and I can't use or return it). Not to mention Advance Auto tried to give me just the cap and rotor when I ordered the entire Opti, so that was a fun little conversation/battle at the counter. "Old" MSD cap and rotor and factory AC Delco Opti had ZERO signs of damage, leakage, zilch evidence of any problems whatsoever. Engine still missing with new Opti. Still no codes. And it won't stay running now, either. Ordered new fuel pump hanging assembly which includes new fuel pump (new fuel pump I installed is now not returnable, either), but part is stuck in Georgia due to "local operational disruption," meaning I won't be getting the part any time soon.
When this entire adventure began back in August I looked all over the engine compartment for any signs of trouble whatsoever. I found a wire running from the steering shaft main wiring harness up around the brake booster check valve, around the driver's side intake manifold, wrapped around the front of the intake around/above the TB to the passenger side intake, and connecting someplace beneath the home plate. This wire was covered in plastic loom. This wire was partially melted and exposed, and the plastic loom had gotten so hot it melted into a grotesque black booger-looking creature up near the brake booster check valve. One of the reasons I replaced that valve was because the mystery wire was melted at that location, I figured the factory brake booster check valve was leaking and it melted the wire by letting hot engine air vent onto it. I also thought replacing that valve would solve the miss. So I replaced the valve with a new AC Delco one, then duct-taped that wire up as good as I could, wrapped it in new loom, and thought nothing more of it. My mechanic asked me what the wire was when he noticed it was spliced into the distributor wiring harness. I told him I had no idea what it was but it was the wire I told him about finding all melted and such. He said it's probably what fried my Opti. Turns out it's a tach sensor wire for my Viper alarm/remote start system. The guys at Best Buy said to bring it back in and they'll fix it when I can get the car there. So that little mystery is solved, but it has nothing to do with the engine miss because we left that wire un-spliced and capped off on the new Opti harness, and I'm seriously hesitant about letting Best Buy "fix it" when we get the car running again.
Cannot tell you how frustrated (and flat BROKE) I am at this point. This car was/is my daily driver and I have been borrowing my mother's car for 3 months now. It's a good thing she's retired or I don't know what the hell I would do. I have a new ignition control module to try next if the fuel pump hanging assembly replacement doesn't work, and after that the GD MSD wires are coming off and new AC Delco's are going on.
I have the EXACT same issue with my 95 Wagon.
Misfires, pings, backfires at WOT and surges/lurches randomly at stop light with foot on brake.
FP is good. Program is good. No codes.
I have been throwing parts at it, double checking plug wires, etc.
Next is the brake booster check valve and the EVAP. Looking for intake leaks.
Here's my thread: http://www.impalassforum.com/vBulletin/showthread.php?t=1238426