pimpinphil

took my car out the other day and noticed a miss in the engine. and really didn't have time to check it over that day, so I just brought it back, anyways a couple days later tried it out again, and have noticed that its missing mainly when im lugging on the engine. if I drive it hitting the shift points, or running it kind of harder, there's no issues at all, good power no problems. however if I, say get it into 6th gear go 65 ish, it miss's, and not constantly, but approx. every 2-5 secs or so depending on how bad I lug on the engine. and it does it in other gears as well, just have to be lugging on the engine.
pulled the codes on it, and the only codes it shows are po 410, and po410pd. which I have disconnected my air system, and never had my computer reprogrammed yet. the plugs and wires only have approx. 8000 miles on it. the car itself has 119xxx on, and really doesn't get driven all to much, this was only the 4th time I brought It out of the garage this year. aside from what I mentioned the coil,opti and most everything else is stock on the engine. thanks for your time.

mrmint69

When mine sits for months it takes a while to get all the bugs out. I will let it warm up good and then do a few wot runs to clean things out. Usually helps and the car runs much better.

pimpinphil

i only take mine out usually to a couple local car shows, and its just the first time i have felt the miss in it. been driven like this for the last 4-5 years or so.

rbremerkamp

I just bought mine 2 months ago, guy said he had replaced opti and waterpump...
Waterpump was new, opti was not. Replaced that and have been good so far.
At that mileage, I wouldn't rule out that being the cause.

I bought one remanned at about $120.

pimpinphil

just and update.
I have finally installed the new opti , installed a Delphi unit from summit-racing. I originally wanted a msd, but they was out of stock everywhere I looked. anyways finished up the install today, and took it out for the first trip. fired right up sounded good, bleed the cooling system, and noticed a rough idle start after working up, not terrible, but bad enough I could tell. anyways took it up the road, still missing, and seems to be at lower rpms. seems to have good power, just missing and kinda shakes around 60-65 mph. no check engine lights thus far. only thing I changed was the opti. going to put in a new coil and coil wire and see if that helps.

parkers Z28

what scan tool did you use ??
On a 97 you have a crank sensor & a cam position sensor
I think one of them could malfunction and the car would seem to have a missfire
do you Know any one that has a 97 LT1 you could swap the sensors ??
also there is a knock sensors...
I think that's were you are going to find your problem
since it only does it when you lug the engine

Injuneer

When you lug the engine, cylinder pressure builds and it requires higher voltage to fire the spark plug. That's when a weakness in the ignition system will show up. Could be a bad wire, arcing wire, loose plug boot, corrosion on the plug wire or coil wire ends, excessive gap on a plug. Could also be a dirty injector. If it's running a little lean on one cylinder, and you start lugging the engine, it's going to knock and the PCM's response with retard would be noticeable.

With regard to the crank position sensor - only on the 96/97 LT1 engine, and only used for misfire detection. Does not affect the way the engine runs. Would not cause a misfire.

Yes, all LT1's have a cam position sensor - it's the optical part of the Optispark. A fault with the cam position sensor should set the normal codes for the Opti.

Do you have access to a scanner that can display"GM Enhanced Parameters"? It should allow you to pull up the misfire count by individual cylinder, which may point you in the right direction.

pimpinphil

thanks for the responses parkers, and injuneer I used a regular type scanner that Autozone or advanced has, forget the name for sure, but its the same ones they use, orange in color.
I have a new coil wire im going to try as well as going to go ahead and replace the coil and icm. the plugs have lower miles on them, as well as the plug wires. if it doesn't get better with the icm, and coil, will check out the plugs and wires again I guess. does autozone have a fuel pressure "checker" as a loaner tool? or what is everyone doing for that? if I need to buy one, does it come with all the right fittings needed for our cars?

I don't know of anyone with this particular scanner "GM Enhanced Parameters" aside from local chevy garage. buts its def. getting close.... love Camaros, but chevy. really dropped the ball on these years. you would think as time goes on you would want things to be easier to work on...
anyways thanks for your guys insight. hoping my issues get worked out here soon.

p.s. you guys have any recommendations on a new coil, msd factory replacement. thanks.

Fatdog2

Might reconnect the air system but I dunno.The engine is still getting lots fuel after you let off the gas,so the air pump helps you out some what.Hope this helps.

Injuneer

The AIR pump runs for a couple minutes at startup, then shuts off. Has no effect on the way the engine runs. It's feeding fresh air to the cats so they heat up faster and start to work.

The engine does not get "lots fuel" when you let up on the accel pedal. The PCM shuts off the fuel to prevent emissions (DFCO = decel fuel cutoff).

pimpinphil

I have been driving it for the last week or so, and it seems to be getting better, im thinking maybe just bad gas now. I still get a slight miss now and again, but its not all the time like it was. ran some injector cleaners through it also.
my car sits a good deal, mostly because I despise cleaning it, so If I don't take it out, I don't have to clean it . but the fuel that was in there really wasn't that old, so I don't know, maybe another story of ethanol??? thanks guys