87 RX-7

iTrader: (1)

Hello again,

I have yet another thing thats bugging me about my 87 N/A 13B. I notice that at 4K RPM the engine slows down, then after that it gains its power again. I'm hoping that it is a fuel filter, since it hasn't been changed for awhile (over 50K miles ago). I will replace this anyways. Could it be something else?

misterstyx69

iTrader: (142)

does it bog?..does it hesitate and then catch again.
Can you elaborate a little more?

RotaryRocket88

iTrader: (7)

Most likely the "3800 RPM hesitation". The secondary injectors switch on at 3800 RPM and 0 manifold pressure, and if this is not done properly by the ECU, it can result in hesitation. The most common source of the problem is poor ECU grounding. There are many threads on this subject, and I think it's even referenced in the 2nd gen FAQ at the top of this section.

87 RX-7

iTrader: (1)

It hesitates and then catches again. One thing I notice is that it doesn't always happen, its almost intermittent. However that said it hesitates more often than not.

Ok! That makes sense. I've been having a couple grounding issues recently. I will take a closer look on the 2nd gen FAQ. Thank you!