KayleeG

I have a 2003 Toyota Matrix XRS, with an automatic transmission. I bought it pre-owned from the dealer in 2007. They had used it as a "runner", because the automatic simply wasn't popular in a "sport compact". (The reason it was produced only 1 year.) I always took really good care of it, and for the most part, it was trouble free for a very long time. I added a CAI, cross drilled rotors, and Hawk ceramic pads. The maintenance was always done "on time", or even before a problem really occured. (Bearings and axles) I had some transmission issues (shift solenoids), which I replaced, and added a transmission cooler (it was running high). I had finally gotten my California legal DC sports exhaust header installed. On my first long drive, I noticed that the "lift" over 6k rpm was not engaging. I checked the oil, and every thing seemed good. A little research suggested the OCV filters may be gummed up. They were clean, but I replaced them anyway. Next, I replaced the OCV. I took her for a run, and still no change. I returned to the house, and checked the oil. 1/2 quart low, not much to worry about, but I figured "maybe because I had everything apart". Again, I drove her down my dirt road to the hwy. I turned left, put my foot on the accelerator, and instantly.. MARBLES! It sounded to me like an engine with really bad timing.. valve and piston colliding. I immediately flipped around, and babied her the 1/2 mile home. Oil level still fine. OCV pulled and tested ok. Valve cover removed, bolts and clearances checked out fine. The noise while there at idle, gets louder as the throttle is increased. Not louder with higher rpms. You can open the throttle at any point on the tachometer, and the sound will get louder. I know the timing is controlled by sensors and the oil pressure. There was no check engine light, and no codes were thrown. I'm at an impasse. A bad oil pump should have thrown a code. It's possible it didn't. If it were bad bearings, wouldn't the noise have "developed", rather than started instantly? I also read a possible issue with a bad oil filter, so I'll do another change. I had just done one about 1000 miles before. Any suggestions? I'm looking to sell it, and really don't want it to need an engine rebuild.