SR hesitation at partial throttle

[harleys]

First off info on the car:

89 240sx Coupe
S13 redtop
SMIC
Tomei Expreme Manifold/Turbo Outlet
T28 10psi
Spec Clutch/Flywheel

And the problem:

In any gear at partial throttle (mainly very little throttle) the car has a hesitation. It doesn't do it all the time, but pretty often. I will just be driving along and it feels like it loses power for a minute, then it picks back up. Under heavy acceleration it runs fine, pulls hard. I searched and didn't really find anything like my problem. I have tried to give any and all information I can think of. any suggestions?

thanks, harley

[slider2828]

I think it might be in need of a ecu tune. It could be running lean and the car just hesitates.

[hayaimoto]

Or it can be a vacuum leak somewhere? Or timing? Good luck, I had the same thing and it was leaking through a small vacuum "T" which caused it to "hiccup" when I let off and re-accelerate.

[harleys]

yah, i'm thinking maybe i have a vacuum leak. i've been running this setup forever, and the problem has just started happening.

[harleys]

don't see any vacuum leaks. anybody have any other ideas? could it be an injector problem?

[harleys]

it's starting to do it more often i think. it's generally when i'm around 2000rpm. any ideas?

[defiantmofo]

It could be a TPS probelm. Mine wasn't registering like 5% throttle, but 100% throttle was fine. Get a volt meter, and check your voltages with the fsm. It should be less than 0.5volts idle, and over 4.5volts full throttle. Not positive about those numbers, so check your FSM

[steve shadows]

shotty wiring and bad condition grounds near the ecu plug

[rps13drift]

spark plugs! check gap and condition!

[mandoz85]

I had a similar problem, turns out my tps was out of adjustment, fixed that and my car ran great again.

[spirit]

I had same issue (would rev to about 1900 hesitate a bit then 2000 and up no problem, only at low throttle)... vacuum line going to the FPR on mine.