1999 ES300 is throwing P0300, P0301, P0306 codes - misfiring.

It's running pretty rough. I tried to read a bit about it but not really drawing any strong conclusions.... Help me out?

1) Depending on the issue, it seems I might find temporary relief (enough to get to the shop?) by running the engine almost to redline and/or adding some fuel additive / cleaner. Should I try this or will it perhaps make things worse?

2) In the current condition, can I drive the car to the shop (no highway, city streets about 10 miles / 15 minutes). Or is that bad and I should get the car towed?

Any other thoughts? Thanks!

If you think it might be fuel related, you can add some Lucas oil fuel conditioner. Works for dirty injectors.

It sounds like it could be a coil problem though.

I am not a mechanic.

Thanks. Okay to drive to shop as-is? Or will more damage result?

I have an OBD code reader with live feed monitoring if there is something else I should try to check. (I don't really know how to use but can try to figure it out).

Perhaps you have some fuel that has water in it. Has the tank been standing near empty during damp weather? Did you recently fill it from some skeevy half-assed gas station?

I doubt that revving it up is going to fix anything.

It could be plugs, wires, or coils. Might even be an O2 sensor. It is somewhat common in the 5 & 6 cylinders, but you have to identify which cylinders are misfiring.

No, air is pretty dry in these parts. And we always use Chevron (at least she's supposed to).

If the fuel has water, symptoms would go away if I top it off? (water floats to the top?).

quote:

Originally posted by rtquig:
It could be plugs, wires, or coils. Might even be an O2 sensor. It is somewhat common in the 5 & 6 cylinders, but you have to identify which cylinders are misfiring.

Scanner is showing 1 and 6 (v6) are having random misfires.

130K miles - I have to check again but pretty sure I've had belts, water, plugs and O2 (and one other sensor) replaced already. But will check mileage.

Water is heavier than ga.

More than likely it’s a bad o2 sensor. On Hondas and Toyotas it’s always best to use factory sensors.

Cylinder 1 and 6 are misfiring.

How easy is it to pull the plugs on these cylinders on your car? I would do that and check the condition of the plugs. Are they fouled, covered in oil, look burned? That could tell you a lot.

Does the car have old school wires and distributor or does it have a coil pack on each cylinder?

How many years and miles on the plugs? Are they OEM plugs?

I would start by checking the plugs as this can tell you a lot.

Change your plugs first, can't hurt.

I always use factory parts (at least shop / dealer are supposed to by request). Except for pads.

I've had Mass Flow and Knock Sensors replaced. Not O2 sensor. I've had one coil replaced (#5?) but no other coils unless they were replaced with the spark plugs.

I'll limp it to the shop unless it's not good to drive as-is.

So, sounds like it could be O2 sensor, coils? It shouldn't be plugs or wires as those were replaced at the dealer 20K miles ago unless something else is wrong that are causing them to go bad.

If the check engine light is on but not blinking it is ok to drive to the shop.

If it is blinking have it towed

Had a VW Jetta do that. Turns out one of the plug wires had a short. Something had worn it down and it was firing correctly when the plug wire was in the right position but if the plug wire moved it would stretch and the copper core had cut so no fire was going to the plug. Easy fix but even VW plug wires not cheap

If it's just chugging along, I'd try to drive it to the shop, but be ready to pull over in case it shuts off on the way.

quote:

Originally posted by smlsig:
If the check engine light is on but not blinking it is ok to drive to the shop.

If it is blinking have it towed

Is that universal? Good to know.

I’ll check if the plugs are easily accessible. But don’t have a socket nor an extension. Would have to go buy.

drive it, you're not hurting it.

something in the ignition isn't right, or at least the computer things so - coil, plug, O2, etc.

2 cyl on different banks sounds like rear 02 to me, but that's a wild-assed guess without seeing, driving & testing.

It's been the plug wires every time with mine.

A blinking O2 light only means its dumping unburnt fuel into the cat.

Fuel, plugs, coils, O2 sensors would be my first guesses.

My Acura had a pretty severe hot start misfire issue, never got it resolved before I traded it in. From my research it was related to a fuel line vapor/pressure issue.