At my wits end with this. A slight hesitation developed a couple months ago. It would appear only during slight throttle on the highway (eg when trying to accel from 73-75). It has gotten worse to the point now that the car will start to die, almost like a fuel cut, even at sub 40mph. I can push in the clutch, rev it out, and it will come back. Sometimes it will go into EML/limp mode and the only way to clear that is to power cycle it. After power cycle it will drive ok for a bit but then back to the stutter. I just replaced the plugs (#1 was stripped ), wires, and bypass valve. The car will drive for maybe 4 miles, then stutter under partial throttle. Again, push in the clutch, "clean it out", and it's good. Plugs were nowhere close to fouled when they came out. BKR7EIXs came out and BKR8EIXs went in.

 

What are the codes that are stored? You will want a proper scan tool that can read manufacture specific codes to get the best help.

 

Just checked the codes, it had a P101F, P1688 and P2404.

The car died about 3 houses away from mine. After restart and taking off it started to hesitate again (in 2nd gear maybe 15-20% throttle) so I pushed in the clutch, revved her out and then it was good for the ~3.6 miles to Advanced Auto and back. No amount of messing with the throttle would get it to die again.

 

P1688 points back to a multitude of problems: stretched belt, slipping belt, failed crank pulley, failed bypass valve, etc. Check your belt for tension, inspect the crank pulley for failure, reach under the intake horn and feel the spring in the bypass valve, they break over time and cause boost leaks.

 

BPV was replaced with a DT one- problem didn't improve. Crank pulley was replaced with a ATI damper a while back.

One thing I can mention is I've been running a Braille 15lb battery for two years. Because of the cold winters, it's gone through quite a few cycles of "dead", "charged", "dead". I have to keep a battery warmer on it while it sits in my (somewhat warm) garage or it will fail to crank in the morning.

 

Just replaced the battery. She fired right up and drove great around the neighborhood. Real test will be tomorrow when I try to drive to work

 

Did you end up finding exactly what the issue was, I'm having this EXACT problem. Just replaced all the ignition coils thinking they were bad, problem still there. Ive also replaced the throttle motor (an expensive $900 part) when I had an EML code last. I do think I have a weak battery, but I doubt that is the cause, but I could be wrong...