Hello, I have a 1992 FD, just fixed an exhaust leak on the turbos and put everything back together. The car runs great - except around 3000-4000 rpm under load it bogs down. Idling the car revs up fine, but driving it bogs it down. I checked the vacuum line routing and put back all of the vacuum lines I had to remove according to the diagram in the workshop manual. I checked all of the fuses and they all have a good connection. I checked the secondary injectors, one of which was loose but I reconnected it and the car has the same issue. I talked to an rx7 shop over messages and gave this same description, and he said it could be overboosting. Has anyone had this issue before? If so what worked as a fix? Or does anyone have any other recommendations or anything else I can check or any possible solutions? Thank you!

 

I had a somewhat similar issue a long time ago, and it turned out to be spark-plug wires with too high resistance. Fouled plugs could also give similar symptoms.

The rotary is so smooth the resultant misfires were not noticeable, and it felt like a loss of boost.

 

I’ll check on my slarkplug wires. Thanks for the feedback

 

Without some kind of data, you're just shooting in the dark and will be guessing until it's "fixed". A boost gauge or wideband will be the way to help diagnose this. Even a fuel pressure tester would help. You would install it and go for a drive with the gauge sitting on the windshield.

With a little digging there is a "hesitation fix" thats somewhat well documented. Although it's not always just a grounding issue. Do some diagnostics with some metrics and clues will manifest