I believe I have some engine related problems.
For one, sometimes during the start up, while engine revs at ~1200rpm, it fluctuates between 1100-1300rpm, lights dim on and off - this continues for about a minute before revs drop down to ~800rpm at idle. This happens occasionlly more so than before.

Second, sometimes when I accelerate full throttle, the engine bogs (around 4-5k rpm), as if spark is cut off for a second.

Third, occasionally when pulling out of gear, let's say coming to a red light, and coming to a stop, engine revs fluctuate +/-100rpm, again almost as if it was about to stall.

Not sure if I have ECU (APRv3) problems or if it is something mechanical. Wondering if anyone has experienced one of these symptons and might have something to add.TIA!

Because it's what you modified. And the first simple test is to put a stock one in and see what happens and debug from there.

I say stock ECU as opposed to stock chip back in the chip carrier - if that's what you've got. Why?

Well because the time my ECU crapped out it was a failure at the chip carrier where the mod chip was. Car acted odd. Kind of like yours.And then at some point would just shut down.

Of course there's a littany of other posibilities. Bad fuel. Messed plugs. MAF FUBAR-ed. And on and on. But many of those will throw an ECU error code - like misfire. And you don't report a check light... So I'd start with that ECU and debug from there.

- Z

Thanks for the reply.
Where I live in north east,temp changes from -20C to +30C could decrease solder reliability, especially ones done by some Joe at APR Vs. Bosch. With that said, my warranty is expired by a couple of months on the ECU and I dont want to spend cash on getting this fixed after just having it over a year...grrr.

Unplug the MAF sensor and see if it helps.

Marcus

part throttle.

Sounds like an air delivery problem. I could be wrong though.

The failure was actually in the chip-carrier socket gizmo as opposed to the solder at the board. I keep a spare ECU, and a spare chip-socket for such debugging now.

Because finding the other PES SC car around at the time and borrowing his ECU was kind of a hassle.

You mod it. Stuff happens. No spare parts. Life sucks. Even with good vendors and kits, annoying things can happen. And your car dealer isn't much help when your mod-ed ECU acts up.

- Z

suggested cleaning the TB. That 'cured' the idle stumbles. Might also be a small vacuum leak. Typical problem area is on the BPV to intake manifold line. The braided OEM hose is prone to leak. And like Rob suggested might not hurt to look at plugs and coil packs.

known good one.

I think stuff had to heat up for the broken trace to separate. But it was pretty flakey at any rate. Maybe if I tapped it when it was feeling like doing it, the problem would have shown itself then.

If you have a non-DBW, you could also remove and clean the sensor located in the throttle body.