I have recently have had my 1995 Camaro V6, 3.4L (Auto) engine replaced and my dad and I noticed that the car idles very rought to the point that it sounds/feels like it will die. We thought they were the spark plug wires going bad, but we replaced the Duralast plugs with Bosch Premiums and yet the car still will not idle normally.

I understand that the car would be rough when the engine is left out in the cold would have a tendency to idle rough, but after it has been running around town or on the highway for more than fifteen minutes it would still shake violently. We have looked on many sites and most of them had told us that the engine mount would usually cause this, but considering that we just had the engine replaced, we would have been told that the mount was going bad. Unless in the month's time that I have had the car back, the mount somehow miraculously cracked or broke.

Any suggestions will be greatly appreciated because we have had this car since it was brand new and I really don't want to sell it.

 

I have seen many times on many vehicles where they swapped the engine and either hooked up a wire wrong, or forgot to ground something. is the check engine light on? you have OBD1 if it's a 95, which means you should have at least an o2 sensor and some form or another of FI, I'd suggest at least double checking all the connections. If you replaced your engine with an engine that's a different size or different specs it's possible that your stall speed is too low (that's unlikely but it happens) ignition timing and valve timing should be considered, it's possible that the cam/cams were installed improperly, it's possible that the ECM isn't getting the right inputs and is in turn changing your ignition timing. MAP/MAF sensor if you've got one. make sure you do a compression test.

just remember you need 3 things for your engine to run, 1 fuel, 2 compression, 3 fire (spark) one of those three is off, either valve timing ignition timing or insufficient air, insufficient fuel, insufficient compression, or weak spark

a good approach to diagnostics is symptom->system->component, you know the symptom, that's the rough idle, next thing to figure out is what system it is, ignition system, fuel system? etc. then from there you narrow it down to the component that has failed.

 

I think those 3.4's have the same coil packs as the 3.8's. If you have a spare plug and wire, attach it to the coil packs and ground the plug against metal to see if you are getting a bright blue spark. A bad/weak coil pack will cause it to run rough. We replaced a 3.8 and the first day it ran smooth, the next day, it was shaking and studdering so bad it would not pull itself. Replaced the coil packs and cam position sensor and it fixed the problem. But as mitchell said above, double check all the electronic connections, pull the codes and maybe they will point you in the right direction. Otherwise, you might be replacing good components.