Assassinxiv

Hey guys I have a 97 Civic with a stock D16Y8. Symptoms: bucking and hesitating acceleration most noticeable it 1st, 2nd, and 3rd gear; between 2-3500 RPM. It doesn't always do it, but it's most noticeable with the engine cold. Seems to be running a little rich as well, new plugs are coated black. NO CEL!

What I have done:
-Cleaned throttle body
-Replaced PCV, plugs, wires, dizzy cap/rotor, air filter, fuel filter, MAP sensor (used known working), ignition coil (from a used good dizzy), upstream o2 sensor (HAD codes p0135, p0155)
-Drove with CAT unbolted to determine if clogged
-Cleaned IACV
-Run Redline SI-1 through fuel
-Checked all grounds.

My next steps: swap throttle body with a know working one to determine if TPS is acting up even though I DID check calibration and it seemed fine.
Replace the ICM (ignitor). Replace fuel injectors (maybe leaking or clogged?). Check fuel pressure to determine if FPR and pump is working correctly. Check mechanical timing.

I try to rule out timing because it is intermittent, and happens only at lower RPM's, but who knows.
Some times it pulls hard, sometimes it feels laggy.
Any ideas? Am I on the right track? I thought for sure the o2 sensor would have fixed it since I had those codes.

maineef

Bump similar issue was wondering if it was the tps? was also gonna check my cat



98 d16y8 all stock

BryanM.

iTrader: (1)

were there any big voltage jumps as you opened and closed the throttle plate?

Assassinxiv

Nope! Swapped throttle bodies with a known working one and still hesitates. It's most noticeable in 2nd around 3k RPM. Checked fuel pressure, 33 PSI so so that's ok.

I have not checked the timing yet. Could not find vacuum leaks. Replaced the ignitor and coil with oem parts, (the dizzy is aftermarket). I'm stumped.

Assassinxiv

I know for a FACT my ignition switch is giving me problems, and will replace it. But I don't think it can cause performance issues.