Car is running really odd.

[95LT1Z28]

Ok, i have an 95 lt1 it has full exhaust, y pipe, longtubes, intake, msd coil, taylor wires, new optispark, and electric water pump. The car will start up, but it takes a little longer then it should. When it starts it will idle perfect and if you take it for a drive after cold start up it runs fine. When you shut it off and let time go by maybe a half hour,and try and start it back up, it will start but when you blurp the throttle it falls on its face, and then the idle will go up and down. Any ideas what the problem could be. Nne of the aftermarket parts were installed by me fyi. I also see some water droplets on the oil fill tube, but no oil in the coolant (when taking the cap off) Could this be a bad opti or possibly bad headgasket?

[krayzie7th]

check engine light on? check your spark plugs and wires and maybe the IAC.

[YZF]

I have heard that the MSD coils have a little too much juice. Ive always been told to run the stock coil.

If you keep driving it after the initial start up, does it run ok until you shut it off? Would it make it across state before it starts to act up or will it do it a certain amount of time into the drive?

[Tyler Wheat]

Just a thought, but you aren't leaking anything out of the waterpump, are you? Maybe its leaking after the car is up to temp...

If the SES light is on, get it scanned and see what that turns up.

Is the new opti an AC Delco?

[95LT1Z28]

Ok, the SES light is not on and doesnt flash or anything, Plugs are brand new ac rapid fires, and wires are newer taylors (on the car when purchased). For the longest time it wouldn't idle w.o. someone applying throttle, and the idle would dip, but after I put the MSD coil on, it cleared up and idles perfect now, but it would still spit and sputter when given any kind of throttle increase, after i switched around the opti vent lines (one un hooked one hooked up to egr port on intake mani) it will take throttle when you cold start it. And yes the opti, i believe is an AC replacement, it has the black and tan cap. The weird part is my dad drove this car 200 miles on the highway before this all started happening.

[95LT1Z28]

Oh and i forgot to add that the water pump isnt leaking at all, i did check into that, and nope no leaks from that.

[Tyler Wheat]

Hmmm... kind of shooting in the dark here. Sounds like you've checked the majority of the common problems and assuming none of the new parts are already failing I really can't think of a whole lot.

How's the fuel pressure look? Might check that just to be sure you don't have a fuel problem, which I don't think you do. It'd be worth checking, though.

The Taylor wires aren't arcing out everywhere are they? They had a big recall on their wires awhile back from what I heard. Thank god mine are fine haha.

You could try cleaning the IAC, but I doubt that will really get you anywhere either. Good thing is, its free and easy.

The ICM could be faulty, but you could also be throwing money away if that doesn't fix it.

How about the opti harness? Maybe you could check that for corrosion/gunk. Just an idea.

[95LT1Z28]

The fuel pressure, i only tested when cranking (wouldnt start at this time) and it was a steady 42psi i can try cleaning the IAC. And no I looked at the wires they all look good. Im stumped to.:embarassed:

[Tyler Wheat]

The fuel pressure, i only tested when cranking (wouldnt start at this time) and it was a steady 42psi i can try cleaning the IAC. And no I looked at the wires they all look good. Im stumped to.:embarassed:

Pop the hood in the dark and start the car. See if you can find anything then on the wires. If they're the problem, you should have a nice little light show.

[95LT1Z28]

ok ill try that later on tonight. Thanks man

[joelster]

Do a cold-start tomorrow, but keep it running until it goes into closed loop and pay close attention to how it "acts" when doing so. I am leaning toward a bad O2 sensor, if you say it runs fine when you first start it up. It should run noticeably different the second it goes into closed loop if it's a faulty O2.

[KissMyWhtSS]

Have you pulled a plug? Fuel pressure seems fine so I'd think it's spark related. I think Autozone can check your coil.

[95LT1Z28]

I also had an o2 sensor in mind. How do you know when it goes into closed loop? And KissMyWhtSS I replaced the factory coil with a MSD blaster coil, because that was one of my guesses to. So thats out. I have pulled the plugs and they do look like the car is running a tad rich, but they arent fouled out, or it would miss all the time not just when the throttle is increased, or at least I think?

[hempkat94z]

If I was you I would get rid of the rapid fire plugs. I had a problem similar to yours and switched to TR55's and cleaned it up until the O2s went bad. This is just mho but it helped with mine

[Fixxer99TA]

Do a cold-start tomorrow, but keep it running until it goes into closed loop and pay close attention to how it "acts" when doing so. I am leaning toward a bad O2 sensor, if you say it runs fine when you first start it up. It should run noticeably different the second it goes into closed loop if it's a faulty O2.

Do this, and tell us exactly what happens. I will also have to say O2 if it starts/runs fine right but starts going crappy when it warms up a bit.