I've been fighting a missfire above 6500 to redline. The car almost cooked itself at the pig roast (appropriate name of our New England July NHIS event). I had no idea just how lean it was running until I spent the last 4 days at the Dyno trying to trouble shoot the problem. Above 6500 the car missfires and the air/fuel ratios go through the roof running in the 14-16% range with the header glowing not red but white hot almost before I can get off the gas. I have replaced the fuel pump, filter, changed the injectors (primary and secondary) with ones just back from cleaning and blueprinting, turned up and turned down the fuel pressure, changed the fuel rail, bypassed the adjustable fuel regulator(and returned to the stock one). I even ran turbo injectors (I know they are not legal but I was trying to get it to rich). I've made 1 change at a time between each dyno run and all the runs are too lean just to varying degrees. I checked for pinched or crushed lines from the tank. Unless someone has a better idea I'll verify that no injector wires are broken on the harness (maybe all this time it is only running on 3 injectors? The front header pipe does seem to glow even whiter) I'll change the MAF and even the ECU. I am seriously frustrated not to mention the hundreds of $$ on dyno runs.
I think my timing is right, at idle leading is at 5 deg after TDC and at full advance around 4000rpm is 25 deg before TDC. Any suggestions are greatly appreciated.

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Jamie Kekeisen
86 ITS RX-7 NER
92 325IS under construction