tjohnny42

Hoping for some guidance: My 2005 Honda Civic Hybrid just recently began becoming sluggish and skipping when under heavy load (up steep hills, etc). The engine light will sometimes flash when this happens and will either stay on after or be off. When staying on, the codes include O2 sensor, all 4 cylinders misfires, catalyst. I suspected either clogged fuel injectors or water in the gas. I have added injector cleaner a few times and dry gas a few times. Doesn't seem to help. The issue happens less often at times (the engine light will be off for many miles) and other times it seems more often. downshifting is helpful for it with the higher RPMs, when climbing the long hills. Any suggestions? Why is it perfect when cold?

Colin42

Timing belt skipped a tooth?

ezone

Hybrid doesn't have a timing belt.

I'd kinda expect it may need a set of ignition coils (8) for the misfire

Not gonna speculate on the rest without a lot more info (exact codes), but misfires can ruin a cat

tjohnny42

The situation seems to be improving. Still happening but much less frequently. Engine light hasn't flashed or come on in over a week. Still suspecting water or gunk in the fuel, OR O2 sensor issue. Does this model have 1 or 2 O2 sensors?

ezone

Good possibility, and just a little bit of water in the gas tank can be real frustrating to figure out


At least 2, and possibly a 3rd sensor depending on which version of the car you have.
O2 sensors don't typically cause misfire codes at random though

mac25

If you want to isolate fuel as the cause, you should be able to lift the rear seats, unscrew the fuel pump lock ring, remove the fuel pump, place the fuel pump in a canister of fresh gas.

Also try checking the fuel pressure, and the ignition pulse (the signal to the injectors).

.........

As well have you check spark while it is hot? You can unclip a fuel injector and pull an ignition coil to check the spark while the car is running.

digital-jesus

Hi.. does your car have an egr? if it has and if the problem is until 2500 rpm try to unclog the egr passages in the intake nanifold. One passage for each cylinder..I had the same problem in a 2001 civic. Sorry my bad english

tjohnny42

So.. the issue was nearly gone, until I just put fresh oil in the engine. It seems to be sputtering more again now.

mac25

What viscosity?

New oil will be thinner across all temperatures, especially while hot. Perhaps you have low compression in a cylinder due to worn rings.

Check compression and report back.

tjohnny42

No one has mentioned clogged cat. Conv. May this b the issue?

Colin42

remove the front O2 sensor (check engine light will come on) and take it for a drive, see if there's any improvement in acceleration/driving