have some q's.
i have a 87 na rx7 gxl.
hesitation in high rpms. not just at 3800. but higher rpms

i have msd. new wires, new spark plugs, maybe 2k miles on the plugs. but ngk plugs. new oil. not synthetic. but the recommended kind by u guys. new vaccum hoses. rebuilt engine not by me, but professionally done. new tires. great condition. where is my ecu exactly, too? new grounds on battery, grounded to chassis and strut, scaped and everything. what else could it be.

 

not quite sure what the problem might be, but you ecu is under the floor board on the passenger side floor.

 

why did you not get NGK plugs? those are the only kind you're supposed to use. not really sure why though.

 

hmm...your a six port right? maybe there sticking closed?

 

have you added any grounds anywhere? try doing this.. start off by adding some 4 guage (batery sized) ground wire from the negative battery terminal to one of hte 4 bolts on the strut tower under the black rubber cover. then lift up your back carpet in the drivers side corner in the very back and youll see a cover with 4 screws and some wire going through the middle (this is the cover for your fuel pump) take that cover off and there is a little black wire held down right in the center of the actual top of the pump housing with a little nut. run at least a 10 or 12 guage wire from it (ring connector bolted down with the original wire there still bolted down) and run it to one of the bolts holding your tailights down and dont forget to scratch the paint off behind the bolt. this fixed my problem and it was doing that

 

i meant that they are good plugs ngk. so i know i dont have to change them yet.

 

Check to see if the aux ports are working correctly. I've seen stuck ports on low milage re-mans. Use the grease test to verify the actuators are moving.

 

But would that cause hesitation? My guess is something fuel related, most likely a clogged fuel filter.

 

I guess it's not hesitation persay, but low power in the upper end. That'll teach me for speedreading. Grounds, Fuel system as well. The aux ports are fairly easy to check first though.

 

If the TPS is about worn out, the ECU will get confused & give random fuel cuts at part throttle.

Using test lights or voltage at idle readings will get your idle setting perfect, but you could still have a worn out TPS resistor.
-The golden test:
Unplug the TPS connector.
Clip a cheap analog (needle type) VOM on the orange & black pins.
Set it to the 1K scale.
Hold off the throttle & work the short range TPS plunger in & out.
You should see a smooth sweep from ~0 to ~5K ohms.
Any bad spots or drop outs in the stroke - it's bad & will give fuel cuts at part throttle.
(Before you toss it, try spray contact cleaner between the sleeve & plunger.)
- Then set it:
Find the fast idle (warm-up) cam & push it back so the throttle sits on the hard idle stop.
Adjust the setting to 1K ohms.
While holding off the fast idle cam, open & close the throttle a few times to see that the 1K setting repeats.