Car goes nuts, intermittently, under weird circumstances.
(I admit that the post title is not the most informative.)
A little background information:
Recently, I installed the A/C delete belt and replaced the oil dipstick tube. Before, there was a horrible clacking sound coming from the engine bay, and I tracked it down to the A/C lines hitting the intake manifold. Looks like the shaft on the compressor is damaged, so I just took it out of the equation. (The compressor is still in the car, just not driven by a belt anymore.)
At the same time, I replaced the engine oil dipstick tube. I had the one from the Malibu (engine donor), but it wasn't the right shape, leaving the dipstick partially covered by the wiring harness. I put a Solstice dipstick tube in, bolted it to the intake manifold and moved on with my life. The dipstick tube is a slightly bigger than the one I removed, though, so I'm waiting for a new dipstick to arrive. (The current one doesn't fit snugly, it's just sitting in the tube.)
Now, the problem: the engine runs *perfectly*, for awhile. The other day, I drove the car around for half an hour without an issue. No CELs, no hesitation or weird sounds. Then, the "reduced engine power" light came on. And, of course, engine power was, in fact, reduced. Still no CEL.
I got the car home, pulled the negative battery cable to reset the computer, started it back up and everything was fine. The next day, I drove it for about half an hour before the problem started again. REALLY bad hesitation, couldn't keep an idle, etc. As long as I stayed out of boost, I was able to drive it, though.
Today, I started it up, and everything ran fine, until I hit the gas (in neutral in the drive way). It revved up fine, but when I lifted it tried to die, basically acting like it was having a seizure. The reduced engine power light came back on. This continued for a few seconds until I shut it off.
Still no CEL.
So, I'm running out of ideas. I suspect there is an issue with the throttle body. When running a compression test recently, I propped open the butterfly valve with a wrench. (In retrospect, this was not perhaps the greatest idea.) The valve seemed like it moved fine at the time, but I didn't spend a lot of time looking at it. If it was the TPS, I would expect a CEL, but those aren't guaranteed by any stretch.
One other thing: every now and then, the air hose connected to the turbo compressor works its way up (and has come off a few times). I have a BOV that's working correctly, though it has a heavier spring than "stock" as I was seeing the valve staying open at idle. Possibly related, but I'm not certain.
Suggestions? The car is an 06 with 55k miles, 8k on the engine, mods in my signature.
Blue-ish 2006 2.4, Werks stage 1 turbo, GMPP cat-back, TCE Wilwood 6 piston front brakes, 4-piston rears , Stainless brake lines, slotted and drilled rotors, DDM braces, BR Racing coilovers, Spec aluminum flywheel, Spec stage 2 clutch, Werks aluminum radiator, DDM oil catch can, Autometer boost, water and AFR gauges, RKSport hood, Morimoto FX-R HID headlights, GReddy Profec @ 13PSI, custom A-pillar gauge pod. Norm's 430 bumper, vented fenders
Currently on engine #4!
Last edited by raygun; 02-08-2017 at 01:56 PM.