Hesitation off idle

[kahunaking]

I have my 93 4EAT car and as soon as it comes off idle it seems to do okay then cuts out until I reduce throttle input. It wont rev past 4200 in neutral or 3000 in drive or if I hold any gear. If I give it more gas it slows down more but if I slowly roll into it the car starts to move better.

It is also throwing code 51 but that doesnt seem like it would cause anything but starting issues but no other codes than that.

[Legacy777]

It kind of sounds like a MAF sensor. Have you tried running the active code check with the green diagnostic connectors? If not, I'd suggest doing that.

[kahunaking]

I have, the only code that comes up at all is the code 51

[Legacy777]

I would recommend following the troubleshooting procedure in the factory service manual.

http://www.main.experiencetherave.com/s ... and_Elect/

Page 217 of 336 has the info you will need. If you have any questions after reviewing the information, let us know.

[kahunaking]

Thanks I will try that when I get home. Im in Tokyo now so it wont be for a while but I will update when I get home

[kahunaking]

I fixed the code 51 by adjusting the switch

I cleaned the MAF and nothing changed.

Replaced fuel filter and it got better but after being under load for a couple seconds it cuts out and wont rev past 3 or so.

[Legacy777]

So no codes are coming up when you check the active and stored mode?

I wonder if your fuel pump is on its way out and is not supplying enough fuel flow/pressure. Do you have a wideband O2 sensor or a means to measure fuel pressure?

[kahunaking]

So in case anyone else has a similar issue, The fuel pump was half dead.

The pump had full pressure at idle but as soon as it started to rev up or be placed under load it dropped hard. I put in a fuel pump out of my 06 STi and it worked just fine and runs like a champ.

[Legacy777]

Good to hear you got it figured out and thanks for letting us know what the problem was.