dual 3 inch exhaust?

How old/many miles are on the valves, valve guides and seals??

i believe everything is original, unknown miles honestly. I guess i'm looking at a head rebuild?

i did a little experimenting today, cleaned the maf, put my new icm in the car, this didn't help. It's not at wide open throttle, it's with any quick motion of the throttle, pretty much regardless of where the rpms are, if i rev it to 2000 rpm, then snap the throttle, even a little bit, the motor will bog down like it's going to cut out, then start to rev up...if i rev slowly the revs come up well, but driving it home from our other house i started to get a slightly choppier idle and louder backfiring...do i have a collapsed lifter?

note to self...start simple...just took a look under the hood, got the car to bog a bit, one of the spark plug wires is arcing quite nicely when the engine bogs down. time for new wires!

Excellent! ....I mean, that it was just the wires.

Have you tried a comp. test yet too?

i haven't done a compression test yet, i've never done one of those before, and i'm not sure if i have exactly what i need to do it/don't really know what i need to do it. i understand the general idea of how it's done, but i think i may just swing by a mechanic friends place in the next few days if i can and see if he can do it real quick.

either that or tell me what i need to do!!

Hey Blue, That hesitation sounds just like my problem before I flushed all the injectors. There is a NOID light that can check the PCM injector leads to make sure they are working.
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huh...it's possible my injectors got a bit gunked up from the car sitting for the last 5 or 6 months, i put a bottle of prestone fuel system cleaner in, as well as a bottle of 108 octane additive, so hopefully when i get some new plug wires on the sucker and drive it some it'll clear out those injectors a bit. The last thing i'm going to do is take the car off the road to have the injectors cleaned, because i guarantee something else will go wrong and she'll be off the road for another few months...maybe i could do an on the car cleaning?

If the heads etc are original then it is safe to assume that the seals, valve or otherwise, have seen better days. A good engine shop could do a valve job, replace the guides and cut the heads for ~150 each.

Over years of use and months of sitting there is a good chance your injectors will need a good cleaning, which can be done later when the heads are off. Typical off the shelf cleaners don't do much. Send them out and have them properly cleaned. Typical cleaning services include new strainers, caps and a before and after printout. I have sent many many sets of injectors to [You must be registered and logged in to see this link.] for service.

Get those wires changed; how old is the Opti?

time to look at the injectors...replaced the plug wires with a new set of msd wires (what i had before) and i put some new plug wire looms on to keep the wires well separated from each other and well away from the headers. It helped a bit with the idle quality, but the car still misses when i move the throttle blades quickly. I checked about half the plugs and none of them were even close to fouled, none of them were wet or anything, they have less than 100 miles on them. I'll pull the rest of them tomorrow to check, but as of now i still have a miss/bog when revving...it seems like i don't have a miss at idle, or it's at least idling well enough that i can't tell i have a miss.

You should add the year of your LT1 in you sig.

LT1 ECU's actually detect and store misfires. If you have, or suspect misfire, you have to scan the computer. Once scanned, the ECU will tell you what cylinder has misfired if at all. The ECU will also tell you if its injection or spark related most of the time. If the optispark is failing, alot of the time, the ECU will NOT display a code (probably due to lack of 5 volt reference sensing but im unsure why). When my opti crapped out, the ECU DID NOT display codes and as a result played with my wallet.

The logical questions you have to ask is; "When did this problem begin?" If it strictly arrived after your header and exhaust work, what along your course of work may have led to this?

Have you checked you waterpump weep hole? Is there any traces of coolant around the optispark?

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i haven't done a compression test yet, i've never done one of those before, and i'm not sure if i have exactly what i need to do it/don't really know what i need to do it. i understand the general idea of how it's done, but i think i may just swing by a mechanic friends place in the next few days if i can and see if he can do it real quick.

either that or tell me what i need to do!!

Its a rather simple procedure. You have to buy a compression test gauge from you local parts house. They cost around 20-30 dollars. You may also rent one from places like autozone or advanceauto and similar places.
1. Take out all 8 spark plugs
2. Disable the coil by removing the connector at the coil
3. Pin back the throttle blade, WOT
4. Thread the compression tester into each cylinders spark plug hole and crank the engine. Take note of the gauges max psi reading and watch the needle for loss of psi.

Once you have all 8 numbers recorded, there should be no more than 10% difference between any cylinder. If you have low compression on just one cylinder, this is usually indicative of a burnt exhaust valve. If you find two adjacent cylinders with bad compression, this usually points to a bad head gasket. And, if all are off the GM stated tolerance, the rings and cylinder walls are worn.

If you find low compression on one cylinder or more, squirt fresh engine oil into those cylinders' spark plug hole and repeat the test to isolate if its either the valves or the rings. The oil serves to temporarily seal the rings and so, if upon re-testing the cylinder, you find a higher compression reading, this means the rings/walls are worn and its time for a bore.....and beer! If the reading stays the same, this means its the valves as oil cannot seal this problem.

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interesting...well i scanned with my computer program (proscan?) and it showed a missfire...all it said was the number 1 though, so i don't know whether that means it's just acknowledging that i have a missfire, or whether i have a missfire in cylinder 1. I'm not throwing any codes...well that's not true, i have a crankshaft position sensor problem, but i've always had that, it's not a recent development, as well as a bunch of emissions stuff that was supposed to be deleted by the guy i sent the computer to...but once again, those codes have been in the computer since i first started the engine. I recently replaced the optispark with a used GM unit i pulled from a roadmaster or something like that. I might have cracked it when i installed it, so i'm going to play around a bit with things like checking injector pulse and checking the rest of my plugs to see if i can find a fouled one before i buy another opti and go to the trouble of draining the cooling system (again...) and pulling everything out again.

Before i did the exhaust i had a bad problem where the engine just wouldn't run right, there was some howling out of the intake which was really weird, and it ran really rough...turns out i had the 02 sensor wires switched. when i switched them back to the proper orientation, the car ran very nicely, didn't seem to bog or hesitate as far as i can remember from driving it around for a bit, it revved quickly and ran great. Then i parked it again to redo the exhaust because i was told that an undersized, non mandrel bent exhaust can cause the engine to run rich (which the car was doing) because the motor can't breathe properly. I'm no longer running rich, because the car doesn't blow BLACK smoke anymore, which it used to do...but now i'm dealing with this hesitation problem, which seems to have come from the car sitting/not being driven for a few weeks after i took it around the block a few times.

car drove alright today, drove it probably 100 miles. It never backfired, but i could feel some hesitation and every once in a while there was a bit of a bump of hesitation (just for a split second) and then everything would smooth out again. At certain rpms i could feel what seemed like a pulsation in the engine...kind of a "voooom voooom voooom voooom" where it felt like the engine was a little out of balance or something...my buddies dad (who's an sbc guy) said that my drivers side rocker arms were making more noise than the left...do you think if i set the d.s. a bit looser than the p.s. it could cause some pulsation?

I recently replaced the optispark with a used GM unit i pulled from a roadmaster or something like that

The Optispark is a PIA when new, I don't know that I would ever trust a used unit out of a junker.....though it may not be your problem I would suggest getting a new GM unit at some point....

Or better yet.... [You must be registered and logged in to see this link.] havent touched my Distibuter in 3 years since I did this.

i've been looking at those for a long time...problem is that is a big chunk of change for a broke college student like myself...guess i'll have to start saving up bigtime

I have a compression test kit from Harbor Freight you can borrow.

I PM'ed you on Rennlist but just found this thread here. I am still interested in coming by to look at the car, I just need to find some time.

hey michael, check my profile page on the list, i just posted something up...

in case you check here first, i'm trying to put together a small get together with my buddies Pat (porschedude1) and Doug (Doug's 951).

maybe some local 948 guys will want to join?