Cause of miss?
 

What would could a slight miss at idle and low rpm cruising? Whats the first thing you think of? I was thinking maybe my wires because one of the boots is bent a little, and 2 of the wires are slightly worn on the outer layer. Its not the plugs, trust me. I also replaced the alternator (DP 160), but you think the battery is really to be ditched due to the last alternator I had that was going? Otherwise I was thinking the MSD coils are fubar, but that I will try to test later tomarrow if I can find time.

coil.

daman, you're pretty sure of that...so I'll take your word for it and do some swapage tomarrow. :wink:

Module
 

I just came back from Mexico two weeks ago, and I had to replace the spark plug Module on my 92' Bonneville. I noticed the car didn't have any power and the engine would shake. I took it to a mechanice and all he did was checked the exhaust, then popped the hood and removed each sparkplug while the car was still running. The two middle cables in the distirbutor cap didn't fire. It was like driving a 4 cylinder and was not burning the gas in the combustion chamber. All he did was replace the the bottom portion of the volt (coil) module and the problem was fixed. I just took it for short ride and drove it at 70mph. This had to be fixed ASAP because the trip back to Chicago was about 2,000 miles. The part costed $1,300.00 Pesos (about$130.00 Dollars) I hope this info. has helped, good luck. 8)

yes, thats one of the areas i'd cover first!! post back.

yup my coil went dead on me...but i kinda noticed back a while ago...round 45 the car kinda does that but if you downshift and bring up the rpms it seems to be fine...but that aws w/ the stock coils...msd i didnt notice it...id check coil...im me later if you have any ?s

Swapped back stock Delco coils and car appears to idle the same and run similar overall. So now I'm thinking maybe my wires are crapping out for a few reasons:

1.) one of the boots is slightly bent = cause arcing?
2.) i had to use some force to fit the 8.5mm MSD wires in the front wire bracket = been told its bad to squish wires
3.) some of the outer insulation was worn by poor wire routing months ago

One last though I'd like to throw out there...what would a damaged IAT sensor cause? Reason I ask is I've been spraying nitrous over it for some time now.

A damaged IAT won't cause a miss, in fact, I seriously doubt NOS will hurt it. It's just a dissimilar metal union (thermocouple). NOS may erode the plastic housing, but not the TC iteslf.

I'd swap back plug wires if you still have the stockers. Short of that, get a cheap set to try. Run with them for awhile if they solve your problem.

If it's actually a miss, it has to be one of these:

Coil
Plug
Wires
ICM
or Alternator (yes, it's true. Trust me)

You've done everything but the ICM and wires.

ok i am having just about the same problem. I was told by a gm expert, jeff lynch, i guess he builds race cars and diagnoses many problems in gm cars that my superchip and 180 t stat was the cause of all my gas dumping and chugging i am getting in my car. so i took out the chip and t stat. The temperature wasnt affected much and neither was the performance of the car. But the car still runs the same. I am getting terrible mileage and the car stutters upon gentle acceleration when taking off from a stop. It is very annoying. Who here thinks I should swap out the coils just to see if thats the problem? Thanks.

Oh and by the way, what is the ICM? It doesnt have to do with the ECM does it? Thanks

Ignition Control Module sits under the coils.