s13 blacktop fuel cut during low acceleration need help!

[lowz 94]

like the title says i have a s13 blacktop i just recently swapped it in. it runs great at idle will rev up and build boost in neutral. now when i try to take it out on the road it gets to about 2000 to 3000rpm im guessing. (tach doesnt work i need to get a dohc tach) then hits fuel cut and either drops down in rpm then kicks back in or it just shuts the motor off completely. i have dug around for vac leaks and cannot find one. i have a walbro 255, new FPR, new ngk iridium plugs, new chasebays harness, and new greddy profec boost controller. would love some more ideas to trouble shoot.

[sleepyS14se]

see it is posts like this that make me hope and pray my blacktop s13 sr20det runs correctly. I just picked my swap up a few days ago and am about to order a wiring specialties pre made harness. my swap is going in my zenki s14

[OnTheChip]

Check the ECU for codes? Sounds like a MAF voltage low problem which puts the ECU in limp mode (actually switches to alpha-N and limits rpm to 3000).

[cotbu]

Your building boost in neutral? not possible, unless timing is so retarded it allows yo to do so. Check ecu for codes and verify base and idle timing. If it's also mafs you should have mentioned the jerking back and forth while driving, when you try to rev above 2500 also black smoke could be present.

[lowz 94]

It wont build boost I mean spike like a pound or 2. Ecu reads 55 normal. And tried 2 mafs and unplugged and there was a difference so maf is functioning thers no jerking just either fuel or ignition cut

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[ultimateirving]

Start with a boost leak test my friend. Will work wonders for you

[lowz 94]

okay did a boost leak test and no leaks. what next?