I have a 1998 Z28 t-top camaro,

This car, when warm will start and run like a bat out of hell.

When it sits overnight, and temps drop below about 40 degrees F, the car will fight you to the death about starting and staying running. It will crank and most days catch and start but you have to keep the gas pedal revved up (2-3000 rpms) to keep it alive. It acts like it's absolutely full of gas. It will "pop" if you let it idle without reving the engine this will set off the check engine light. Dies if you let your foot out before its warm. If you keep it revved up long enough to get it warm, it will then idle, then will run beautifully, and start and stop as much as you want .. until it sits overnight.

Here goes... we've changed, replaced, tried..

temp sensor
air temp sensor
plugs
wires
oil
oil filters
air filters
thermostate
flushed/replaced anti-freeze
new battery
new alternator

I have also taken my car to the chevy dealership and they tell me the same thing. Misfires, multiple or random cylinder(s), do a tune up. Of course they look at me like i'm stupid when i explain what is going on (probably because i'm a girl) and i never get any straight answers.

anyone that can help or give suggestions will be greatly appreciated!!!

 

I came in here to write 'temp sensor'- but, if you have replaced it with a KNOWN good one, and this continues, then start checking the wiring, connectors, etc. Sounds like it might be an intermittent open, which can be really difficult to track down. Can you borrow a scanner and see what the various sensors are reporting when it is cold and not running well?

 

If you have a 98 Z28, you have the LS1 engine, not an LT1. You posted on the "LT1 Based Engine Tech" forum. I'll move it to the LS1 Engine Tech forum for you.

 

Yup, sounds like a fuel trim problem. You really need a scan tool to see if there's a sensor throwing out a bad reading, etc as already mentioned. Misfire codes don't tell you much...

That dealer sounds pretty lame- all they want to do is rake in the mulah on tune-up labor and parts but don't want to do any difficult diagnosis (and how hard it is remains to be seen).

I would find a reputable shop that seems confident they can fix your car without just throwing parts at it.

Only other suggestion is to unplug sensors and see if it runs better without that reading. Might be helpful on the ones that are easy to get to, at least.