2003 protege 2.0 stalling problems

[derfernerf]

I've got a rough idle and sometimes stall in my 2.0 Protege.

I'm going to start by saying I have no cat, I have the pre-cat after the manifold and between the j-pipe, but the one under the car cracked and I replaced it with a piece of pipe. I wasn't paying the price of a new one. Could this be messing with the o2 sensor? I've had this problem before when I had a cracked header, but replaced everything back to stock and it was okay.

Now heres the catch, the other night I was out, and it was sputtering at lights, but I made it to where I was going. I went to leave, it started, I drove about 50 feet, came to a stop and it stalled, and it turned over but didn't start the first time I turned the key, so I backed off and tried again and nothing. Didn't turn over. Jump started it and it started right up, and ran, but sputtered, for awhile, and then seemed fine before I made it home.

I can feel a sputter/misfire when I let off the gas (Coasting down a hill for example) but seems fine when I am on the gas.

It also doesn't seem to be a problem when it's cold, but once it's up to temp it does it for awhile, and then seems to go away after awhile. It's getting worse and worse. It would only sputter for a minute once up to temp, but now it does it for 20+ minutes.

2003 2.0
Auto trans
143k Miles

Also, just did a valve cover gasket because it was leaking oil out the front

 

[concept]

It could be a vacuum leak caused by an unplugged hose, a cracked intake snorkle pipe or split hose. Even a bad spark plug or spark plug wire would cause running/idling issues. Start by checking all vacuum hoses and spark plug wires.

 

[elooto524]

If the valve cover gasket was leaking oil prior to this problem, try replacing the coil packs. My 02 Es was doing the same things and it fixed the problem

 

[derfernerf]

Plugs and wires are pretty new (year and a half old), I replaced one of the coil packs because it crack in half trying to remove it (They get really brittle in the cold, less than a year old coil pack broke in half)

The problem was happening before the valve cover job, but it has been getting worse and worse

 

[njaremka]

EGR or MAF

Both of those will cause issues before throwing a CEL, and both are a b**** to diagnose. if your coils-wires and intake are all in great condition, my bet is on one of these.