So I took my car to the 1/8th mile yesterday (best e.t. of 9.69).
And on my way home on the interstate my car seemed to be fuel cutting. It only happened between 4500-5000 rpm. And it only happened if I kept the engine at a steady rpm in that range. So if I revved it through that range it wouldn't have any issues, and if I drove it through that range there was no issue. Any ideas? I was thinking maybe an injector is getting clogged or something. But that didn't make sense after I figure it was only between 4500-5000. So my next thought was maybe the O2 sensor is getting a funky reading. Should I just get my car read?

Mods list if it matters-
GSR swapped '91 hatch
Full exhaust
B16 LSD tranny
Full Rywire dpfi-obd1 GSR harness with jumper harness

Thanks,
Sawyer

 

I would test the TPS, possibly developing a "dead spot".

If you keep the gas pedal at that 4500-5000 spot and engine starts to "stall" and you do not move the gas peddle, what happens?

Will engine stall completely or will RPM just drop to an idle? 94

 

It will just cut for a split second when holding steady anywhere between 4500-5000. That's when I keep the pedal at the some position. After it cuts out it picks back up. And its not just an isolated problem once. After awhile I backed it down to 4k and it didn't do it anymore.

 

I would still test the TPS.
Random misfires are most commonly due to a fuel issue, fuel pump, PGM-FI Main Relay, fuel injectors or the ECU/ECM controlling of the injectors, the injectors themselves, because this seems to happen consistently at 4500-5000 RPM, or that throttle position I would suspect the TPS, if the stall happens in any gear at 4500-5000 RPM then it is unlikely to be the TPS is it will not be in the same place in all gears.

The question is, is the "stall" due to no fuel or no spark? 94

 

I'm not sure. It doesn't seem to pop once it fires the next time around. So that could rule out spark? Because if it isn't firing then the gas would load up and once it does fire the next time around it would ignite all the extra unburnt gas?

 

I agree, unless maybe if the spark is just getting weak, but it sounds more like a fuel issue, have you checked fuel pressure, would be nice to know if fuel pressure changes at all when engine is "stalling", if there is no change in fuel pressure you will know it is not the pump or the PGM-FI Main Relay, [or anything else up to the rail, leaving only the injectors, ECU/ECM or sensors controlling the ECU/ECM. 94

 

What would be the easiest way to check fuel pressure without going all out and installing a fuel pressure gauge? And what is the PGM-FI Main relay