Here it is,

My camaro has a 305 TPI engine and a five speed transmission. I recently replaced the stock exhaust system with 2 1/2 pipes and a flowmaster muffler. I also got rid of the catalyst converter for better flow. Needless to say it, the car now sounds great and it runs better.

Well, only for a short time. After the upgrade, I immediatly noticed that the engine kind of hesitated a little on first and second gear. Later, it got worse, the engine started running very rough on fourth and fifth gear. I replaced the spark plugs with new ones, the old ones were a little black. I also replaced the wires, but used a used set (supposed to be good). The car got a little better, but it is still running rough. A slight smell to gas can also be noticed when the engine is turned off. Would it be that I need to replace the spark plug wires with new ones? Or, would it be that the engine now needs more air due to the bigger exhaust system? Perhaps I need to replace the MAS sensor? Hope not.

Any suggestions will be of great help.

jangel59@yahoo.com :hail:

 

Welcome to thirdgen.org

If all you did was run a new exhaust, I'd suspect the o2 sensor...everything else you mention is not related to the exhaust system.

Edited:

I might add that you were probably already running rich before...removing the cat now lets unburt fuel through....soo, you may have another issue as well.

Scan the ecm while running, see if a rich condition exists...also pull the codes from the ECM an see if a code 45? is there.

Oh, BTW, your '90 TPI doesn't have a MAF (MAS).

 

Great, I'll try it. Thanks for the info and the response, will let you know what happened.

Joe

 

You won't believe what was really wrong with my car, the real problem I had were two spark plug wires crossed, number 3 with number 6 at the distributor cap. As soon as I placed the wires in their correct position, the car went back to running smoothly. How dumb was that ah? I should have double checked this first of all.

Now, I still notice a slight smell of gas when I start the engine. How exactly do you scan the ecm?

Scan the ecm while running, see if a rich condition exists...also pull the codes from the ECM an see if a code 45? is there. Scan the ecm while running, see if a rich condition exists...also pull the codes from the ECM an see if a code 45? is there.

Also, my tachometer needle is stuck at the highest position, it only moves when I turn off the engine, but pretty much stays all the way to the right. Do I have to replace it, or is there a way to fix it?

 

https://www.thirdgen.org/newdesign/faq/thirdgen.shtml

check your tach wires connection on your distribuator.... wire may be loose or a bad tach...

dont know how to replace it though