89 S13 Hesitation?????????

[mgp87zxt]

I am having some hesitation on an 89 s13 but it is different than anything I have seen before.

It happens anywhere below 3500 rpms and feels like an ignition or fuel problem but I dont understand why it happens just on the bottom end.

Also only happens at partial throttle. its fine on the bottom end if you gun it. "maybe o2 sensor??"

Im going to make sure I dont have a bad tank of gas becuase it has been raining around here alot.

sound familiar or anybody have any ideas?

[ride4lame]

try new spark plugs.. i was having similar problems and that straightened it out.

[89240sx]

sounds exactly like my 89 and it was a bad EGR valve! ... to test unplug the vaccuum line from the top and put a screw in it and then drive it and see if it stops.