Rewind to a couple days ago. I found a small puddle of coolant under my car dripping from right under the crank pulley. Immediatly i figure the water pump was done and needs to be changed. Past couple days, nothing on the ground. But you can see the coolant hanging on the bottom of the block. So i know there is a slow leak.

Fastforward to today, i got my pcm4less tune and put it in and took the car for a spin (throws a P1657 code for some reason but thats a different story) and the car was spuddering in higher rpm ranges with my floot through the floor boards. If i take it up to 5000rpm in first or second gear, the slight stumbling occurs at around 3800-4000 to 5500 (when ever it wants to inbetween, sometimes not at all) So i change back to the stock pcm, same issue.


Other then this issue which JUST started tonight, was fine earlier. The car runs damn good, and pulls strong.

Work recently done

Walbro255 pump with wiring kit, plugs, wires, fuel filter, long tubes, ory, egr/air/cat delete. Car basically had a full tune up 3 weeks ago.
Car smells like its running rich, i have 2 new o2's waiting to go in.
I want to make sure all the excess ceramic is burnned off the headers first.

Am i right to think the opti is about to kick the bucket because of the coolant leak from the waterpump?
Also could fouled o2's be causing this high rpm stumble?

I imagine ill end up doing a new optio and water pump with gaskets anyways, but would rather be sure before i go and dump $800 heh.

Thanks in advance


P.S Someone at my shop mentioned maybe a broken valve spring? Im sort of doubting that tho as the stumbling seems intermittent. Thanks again.