Ok I got my 95 Z the other night, and low rmp round town riding it shifts ok can't tell if its a lobe from a cam or miss from what I think is wrong with it. The guy I got it from said the LT1 that's in it come out of a Vette but he said they didn't do anything with the ecu when they did the swap. When I'm in it off the line it will rap out but I have to let off and get back in it to shift and in second also but at high rpm it cuts out. Does the ecu need remapped or what ever for the different motor or any ideas? It does have headers and true duals on it. I was noticing that there are times where it runs smooth like a top and then it will go to the rough idle and kinda missing out. I can't see that being plugs and stuff.

 

honestly, I'm lost

would you mind posting again and please be clear and specific

 

Clear and specific on what part?

 

Need to be more clear on what you're saying as far as what the vehicle is doing. It seems jumbled and unclear when reading. I think I might understand but then again assumptions aren't the way to go.

It rides and shifts smooth while slow cruising, yet when you get on the throttle is when it begins to act up? Shifts rough and cuts out at high rpm's? What do you mean by cuts out, or "raps" out off the line where you let off the pedal and get back on in order to shift...?

 

Ok....like when I get in in the morning it starts and runs like a top nice and smooth like a new z. After a bit sometimes a few blocks sometimes a few miles it starts to have what a call a "miss". It runs rough, idles like its got a big lobe cam when you punch it it continues and like shakes through out the whole car. And after a bit of it running like that it will go back to running smooth. I was thinking tune up like plugs and wires but why would it run so good and times when its that. The shifting thing I believe could be something different. Was thinking maybe one of the sensors is bad or going bad? It's got long tube headers and straight pipe exhaust so no o2 sensors on it was thinking maybe that but I think it would be all the time with that. It does also have a cold air on it too. But like I said the shift points at high rpm like when its floored off the line don't shift like where I feel it should shift like before it gets to any of the red line marks on the tach. But I think that might just be needing a ecu tune for the adjustments cuz it shifts fine when you're not ***** to the wall.

 

The motor is out of a 96 Corvette the ecu as I was told was not touched since the swap. I've been told that not everything on the 96 Corvette is the same as on the 95 Z28 even though they are both LT1's.

 

Drive it around until you get it to run rough. Make sure your close you home. Then take the plugs out and see how they look. If they are carboned up replace. If they are soaked with fuel check the injectors and look into new plugs. If they are white from running to lean you have a tune issue or fuel problem.

 

Quoting: After a bit sometimes a few blocks sometimes a few miles it starts to have what a call a "miss". It runs rough, idles like its got a big lobe cam when you punch it it continues and like shakes through out the whole car. And after a bit of it running like that it will go back to running smooth.

Mine has the same problem. It's intermittent. Varies on how long it takes until it starts but it shakes and stutters, I've replaced a lot of things and done numerous checks. The previous owner didn't take care of this car at all. I am still unable to figure out what is causing the actual problem though.

 

This one wasn't either. I had someone tell me it was my crank sensor if I remember right or one of them because between 95 Z28 LT1 and 96 Vette LT1 they went from a low voltage one to a higher voltage one and you either get into the ecu and install a resistor or change the one on the motor to the old style for the computer to read it right. I've also wondered bout it being the o2 sensor since I got headers and no cats and o2 sensors

 

Why would it be intermittent? Like I said it runs fine at times and others not....its why I'm leaning towards sensors and ecu tune not plugs....if it was plugs it would stay rough constantly and not get better just stay crappy..