93Euphoria

Ok guys so allow me to explain my situation thoroughly. I did what most guys wouldnt do to their LT1’s and drove round trip of 9000 miles and she ran great with all the high consistent rpm abuse on one oil change.

Now recently since im back home she drive fine when warm or just began driving from cold start, but once its on normal operating temperature [for my car reads (175-180) on the highway and about (190-200) in the city], It gives me bad hesitation problems upon acceleration in low rpm when I give it more then usual throttle. It accels fine in any rpm higher then 2200. Just feels alittle power loss. It only does this when its as warm as it’ll get. Things ive done and checked. BTW, I love how everyone like to blame the opti but I doubt it but then again you never know.

-Practically new AC Delco Opti (20,000 miles), Checked it and its as clean and dry as a desert!
-New MSD coil
-New but cheap summit opti wires, checked them and no burning or abrasions. All plugs in tight.
-30,000 miles on plugs

Hesitation goes away when I shift down for a high rpm upon accel. Car hates low rpm for some reason. I always put in 93 octane.

I came to a conclusion that maybe its my old worn out O2 sensors or something drowning from heat soak. IDK you guys give me ideas.



The other issue is the oil issue. Last night I checked the car before my trip to Miami today and there was a minor oil leak from the back of the engine. I was thinking either the rear main seal or the intake. Then today she drove fine with no issue but once I got off the exit in Miami in stop in go traffic I saw alittle smoke coming from the back of the passengers side of the engine. It smelled like burning oil but that leads me back to what I think it might be (rear main seal or intake leak). Checked the oil and its has about 6 quarts of the regular mobile 1 I recently changed to after the alaska trip.

Please tell me if you guys have had this same problem simultaneously and if its just one broken thing causing 2 different issues or just 2 things that need replacement.

One last words is these problems didnt occur until after I got off I-95. Got to a Girl Friends house in Miami and checked everything and like mentioned earlier the smoke and the bad hesitation in traffic. I let the car cool off in the driveway and sit for about 20 mins then started her up to run to the store and she ran fine without a problem for about 10 mins then the hesitation came back. Once I left her house came back home to orlando and the oil issue and smoke didnt comeback. IDK maybe the car needed to get rid of some excess oil or something. Lol these LT1’s are bipolar and now im finally realizing why they get so much hate. But I love my car more then any girl out there so far and I will do whatever it takes to get her back into 1993 shape. As mentioned in earlier posts its listed as a 94 but has a MAF sensor. Checked that and it was clean as a whistle.

Any tips, ideas, and help will be greatly appreciated. Sorry for the long A$$ post. lol

93Euphoria

As far as the O2 sensors would the computer notice it leading to a check engine light? Because there is no check engine light. The only light is the coolant level light comes on due to from my knowledge a foul coolant level sensor. And thats has been coming on for the past year.

And for the oil leak would an intake leak lead to a vacuum leak causing hesitation when warm?

As stated earlier the new ICM coil is only has 10,000 miles new from MSD and if I should get washers in hopes of dissipating the heat soak?

Any help. Thanks

93Euphoria

Already did plenty of searches but want to make sure from a few guys. 100 views and no one has any ideas?

93BlackZ28

iTrader: (5)

The hesitation at certian temps is kind of odd. Not sure what to tell you about that. My first guess would be a coil probably cause when an OPTI goes, it usually goes quick and dies.

These cars are known for leaking at the back of the intake and thats most likely where yours is leaking from. I would have to think that it is 2 seperate problems you have and not an oil leak causing the hesitation.

93Euphoria

Thanks. Any little words will help. If its the coil I would think that it wouldn't be since its new MSD. I guess an upgrade from the stocker. Maybe I need advice if I should get washers. Both Opti and coil & wires are new. But I must admit im not the most patient of all people and if I get more replies about these issues would be great. I would think shbox or some of the other big experienced LT F-body members could chime in. lol im in a bit of desperation here and im trying to be patient with my car.

Oil leak I would believe its the back of the intake, hence smoke from the back of the engine. Hoping its not rear main seal because thats a $600. IDK I need more answers. I though that maybe an intake vacuum leak but the hesitation would happen regardless of the car temp from my knowledge. I checked all hoses and seals to the intake and they are all good and sealed. Im going to have to let the car cool and feel if I find oil leaking from the back of the intake.


Now today this morning there is water leaking in the car im going to have to make separate threads for now 3 issues. There was a puddle of water on the passenger side floor under the dash and feel moist on my drivers side on the carpet under the dash. Could be AC or something. No floods have been in my garage......

Facepalm with my car!!!!!!!!!

93Euphoria

As far as the O2 sensors would the computer notice it leading to a check engine light? Because there is no check engine light. The only light is the coolant level light comes on due to from my knowledge a foul coolant level sensor. And thats has been coming on for the past year.

Im 100% certain that someone with their LT1 has had these same hesitating issues. I just need to confirm if it sounds like O2 sensors, Heat soaked Coil, EGR valve, or the combination of the above or something other. I could just take it to a shop but they want ed to ask the forums with people that have more knowledge on LT1’s...

I apologize for my impatience but really? No one has come to a conclusion yet? Maybe im not explain it enough or im explaining too much to the point where no one wants to read. lol

But incase anyone asks the ignition system is all new. Injection system is old but I would think that if its the injection system it would hesitate (giving it more throttle then usual upon accel) before it got to normal operating temperature. Any helpful advice wouldnt be deeply appreciated. I know its not a performance thread. No wonder why its not seeking interest. lol

93 LT1 Vette

Pop the ICM off add some more di-electric for a better sink and see if it helps.

93Euphoria

Ok update checked if there was an oil leak in the back and felt around and didnt feel anything. Felt dry...

Ok thank man appreciate the tip. Ill try that with a few spacers and see how she does. I wonder if there are rubber spacers. Ill try hardware store. The coil is new but (correct me if im wrong) the plug ICM is stock.

As far as the O2 sensors what are some signs of them going bad?

slingshot928

My MSD coil just died on me after 20k miles...I had a miss at low rpm, changed plug wires, icm, problem didn't go away in the past two year. Put a new ac delco coil on and the car runs great, no hesitation or running rough at low rpm. A new ac delco coil is $40 on amazon, doesn't hurt to try. Some think the msd coil is actually worse than the ac delco.

If you have a 93, you can check the codes by shorting out the top two right pins of the ecm connector under the dash and then turning the key forward. More info is located on shbox.com. Codes 41 and 42 are for ICM / coil related.

Did you put your hand on the back of the motor, the valve covers could be leaking onto the exhaust or like previous post, the intake.