92 Civic Bogging/dead spot while accelerating

Maintenance/Repairs
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1

Year : 1992
Make : Honda
Model : Civic VX Manual
Engine : 1.5 d15z1
Mileage : 266k

My car started to bog/dead spot/ hesitation while accelerating around 1.5k rpm to 2.5k rpm all the time in every gear but less in 4th, 5th. After 3k rpm it runs smooth. Sometimes it’s so bad that I have about 4-second dead spot while accelerating and it’s getting quite dangerous to drive around traffic

So far I have changed,

Fuel filter
Fuel pump
Spark plugs

and cleaned

injectors
intake manifold
throttle
map sensor

I have ran my car under an open loop by taking out the O2 sensor and it runs like brand new. Next thing on the list for me is to adjust the ignition timing but my question is

Since my car is running perfectly on open loop, can timing be still a factor to this problem?

2

So?

Why haven’t you replaced the O2 sensor?

This engine management system is OBDI.

And OBDI isn’t exactly accurate when reporting the condition of the only O2 sensor in the engine management system.

Tester

3

Sounds like changing the O2 sensor is the next best step. :grin:
Nice work, by the way.