My Neon runs rough when you first start it

I know of the Chystler knock. It does that a lot especially when it's idling, but when I first start it it seems to miss a little and run kind of rough. This happens a lot worse if the car has just been sitting there for say 2-3 days. My fuel pump relief valve is crappy so I have to turn the key forward to get the thing to get some pressure in the line so the car will start. I'm wondering if that's my fuel pump relief valve causing the problem by not getting enough fuel to the engine when you first start it because it's bleeding the pressure or is it something else? Thanks.

when you say rough...you mean it sort of shakes and just doesnt feel as tight when you accelerate and brake? Part of the problem is probably just because its cold...it takes a few minutes to warm up.

It jerks a little when it starts up and knocks kind of loud. A guy at work told me it could be my fuel filter.

Rod Knock?

I think it has a little psiton slap. I'm not quite sure.

First, do a tuneup.

Sendon, check the front motor mount.

The rattling noise is piston slap and is normal.

That;s funny how they say piston slap is "normal." :D

On a Dodge Neon 2.0 it is normal, hell even new ones have piston slap on cold days.

On a Dodge Neon 2.0 it is normal, hell even new ones have piston slap on cold days.

Well I think any of Chrystler's 4 banger 2.0 to liek 2.4's do it. I've heard it in a plymoth shadow and some other neons.

The shadow has the 2.2 which probably hads the rod knock which is not piston slap.

Piston slap only occurs when the engine is cold and goes away once it is warmed up. Rod knock like what is heard when a shadow is running is constant all the time.