95 LT1 ZF car

Background: Last month I did plugs and wires and the front coolant temp sensor since I broke it getting the belt off. Had a hell of a time getting the car to start. Changed coil and ran fine. A couple days later I got a C26 code and the car was having trouble starting. It would take a while to fire. Changed the purge solenoid on the intake and the rotten vac hoses that were attached to it. Didn't change anything and CEL was still on. Since the car still ran and functioned other that the starting issue I decided not deal with it at the time since the issue only occurs when the car is warm. First start in the morning fires right up.

Now: Today I did a coolant service because I don't know when it was last changed and according to the analog gauge I was getting too warm on hot days or slow driving. Come to find out that the digital read out shows about 50 degrees cooler, but still some fresh coolant seemed like a good idea. It was very hot here today (91 degrees) and the car was having a lot of trouble starting. Would just sit there and crank and crank, turn it off try again and then it would finally fire, but now would shoot up to 2k rpm and stay there for a bit and then slowly the idle would come back down. Took it for a test drive to make sure there were no coolant leaks and got one hiccup of where I applied throttle and the car seemed to stumble n itself, but only happened that once, parked got dinner to go, and had the same long start and high idle combo but to add to the fun now my once previously ice cold A/C isn't making any cold anymore. Or at least wasn't for the drive back home.

Guys I have tried the search function and got some ideas, but still feel really lost and frustrated. Any ideas or thoughts on what might be happening would be greatly appreciated. I feel lost with trying to diag this and I have not had a chance to buy and FSM yet.

Note: I did run out to the car to check codes and I have
1. C12
4. H36 , H15
A. H26

Also I am not the first owner and as far an I can tell most of the car is stock. There is an MSD conversion already on it. At least the control box and had an MSD coil and wires before with the incorrect spec'd plugs, can't see if the Opti is MSD, but with 190k miles and the whole MSD kit I think it would be a fair assumption. I installed AC Delco plugs and wires and an autozone coil cause I was in a rush. Not sure if those are just not playing well with the MSD controller, but I can't see why that would be the case.

 

Morning update: So I thought possibly that there may have been coolant somewhere it shouldn't have been last night so I hoped it would have dried out and I went to start the car. Fired right up, first try and the A/C was back to working. So I shut her down. waited a few seconds and went to start her again. Started up after a few more cranks than normal, but still had a/c and the cel was still on. Gave it just a nudge of throttle and it killed the engine. Checked the code and got 1. c12 (I know this is a good thing) but also 4. H36 and H15 which seem to indicate a coolant temp sensor issue which is frustrating since that is new and a faulty high res pulse from the Opti. After reading the code I went to start again and the car took many cranks to start. So much so I had to key off and try again to just get to start. Now though there is no A/C function either. Turning on and off the a/c does initially affect the engine rpm, but it settles back out ( I believe this is normal function) and giving light throttle does seem to try to kill the engine by significantly dropping the revs at first. If I push through that, the revs will raise back up. It isn't consistently killing the engine, but enough times sitting there to really worry.

Any ideas?

 

Yeah, I have one: the symptoms, i.e., easy cold starting but difficult hot starting, especially after being shut down for a few minutes before attempting to restart is classic flooding symptom. But, that can be easily eliminated if you hold the accelerator to the floor ("clearing flooded engine mode) and crank it. IF it will start then, it is an indicator of excess fuel - .

But, that said: a dynamic scanning will yield a wealth of information. Do you have an FSM??

And, when reading the plugs, is there signs of rich (OR lean)?

I loved my 95 LT1 Vette. Once I was outfitted with my own scanning tool and was able to put everything right, far as sensors and parts, etc., that 95 was one sweet, sweet running, beautiful SOB! Wish I could have afforded to keep her, but had to trade to buy the ZR-1 I have now.. Hope you get yours running now too!

 

I think the Opti is on its last leg hence the 36 code.