81cuttysupreme

So my engine recently started having problems. It's a forged 347 and I'm running a d1sc. When I had it tuned it ran great for about the last two years. Recently though once it warms up and goes into closed loop it starts stuttering, especially around 40-50 mph in low gear, 4l60e. I've changed the maf, and the o2 sensors, and the fpr, because fuel pressure was high. I swapped fpr and o2s at the same time and it seemed to help, but not fix the problem. There are no codes. The engine seems to run fine in open loop but not closed loop.

I'm stumped, and don't want to continue throwing parts at it. Help!

2xLS1

iTrader: (25)

You can't diagnose modern EFI without a data logging scanner.