This problem is kicking my ***. I have an 88 TII, mods in sig. Im getting a hesitation in open loop when cruising and accelerating. My AEM wideband shows the AFR getting into the 16-17's when it happens. Usually in open loop, i get 12-13 AFR. When it goes into closed loop, it runs fine. Even at idle, ive noticed the AFR rising to 13's when it is usually around 12.3. The problem slowly reared its head over the past few months, now it is very noticable. It used to only happen when the engine was not warmed up.

This is with new RC eng 750cc primaries (low-imp), newish 02 sensor. Ive tried
cleaning groundes (under uim, driver's side strut, ecu, etc), replacing the spark plugs (both were the same light tan color - running lean?) and fuel filter, no help. Unplugged TPS, no help. TPS has no spikes when logged on the rtek. If i unplug the o2, it is almost undrivable, AFRs in the 16-17's. I can get it to run better by adding fuel with the rtek, at +15% correction.

It runs perfect in closed loop. I just made a 200 mile trip with it, no problems on the cruising on the interstate. The only thing I can think of is that the new RC injectors are on their way out?? they are less than 2 months old though. I am about to swap them out for my old 550's, and wanted to see if anybody on here had a similar problem and fix, to save me the trouble

and i have an rtek log of it happening too. The injector d/c is at 5%, AFR in the 13 range, then when it happens, the AFR drops to 16-18, yet the injector d/c is up to 7%?? I can post it when i get home tonight

 

I have to wonder if it is the Rtek. I have the same problem.
Chris