4000 rpm hesitation

[s13240sx]

Hey
Ive got a 91 240sx and im getting some really bad hesitation from about 4000 and up any tips. Im thinking maybe its a grounding problem anyone else having any problems.

[Foxcolt]

Check your sparkplugs for severe carbon deposits.

[kandyflip445]

It may be fuel too. If you haven't replaced your fuel filter lately now may be a good time.

[sL103]

-fuel filter
-spark plugs
-spark plug wires
-pcv valve and hose
-distributor
-CAS
-alternator
- maybe a grounding prob you can get kits for that the help believe it or not
-injectors possibly

but more than what im guessing it could be is that 300ZX 90-96 had quite a bit of the same problem but a thing you might want to try is getting some eletrical cleaner and some steel wool or sand paper and clean off all the connectors anyone that you can get or reach too that can actually go along way it sure does on the Z

[240racer]

This also sounds like knocking. Sometimes the computer senses knock and retard the timing, which makes it hesitate. This could be because of the timing not being set correctly, dirty fuel filter, bad gas, stuff like that. I heard that the knock sensor is disabled at like 5500 rpm or something anyway, but whatever.

[s13240sx]

I replaced the plugs and fuel filter when i got the car less then a month ago, about the knocking it does it wither or not its WOT or just barely depresing the gas so i didnt really think it was that.

S13240SX