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Brief power loss when warming up - Ah ha update!?!

All,
I have an 03 civic which has recently exhibiting rather inconvenient power loss during warm up.

It seems to be worse when it’s below 35 F out… The car starts just fine and I can generally drive several blocks just fine as well. Then for no apparent reason, the engine loses basically all power. It doesn’t stall, but there is basically no power. When I pull over, the idle falls to ~400-500 RPM. Pumping the gas increases the RPM slightly, but again, there is no power. Then as quickly as it began, the problem disappears; the engine returns to normal idle/power. This never reoccurs if the engine is kept warm. However, if the car sits for a few hours, the problem happens again. I would estimate the power loss occurs for ~30 seconds. The check engine light does not turn on before, during or after these episodes. It’s almost like the choke is sticking… Any ideas?
Thanks in advance for any help!
j

Has The “Check Engine Light” Illuminated ?
CSA

No, the check engine light does not come on before, during, or after the power loss.

I had a similar problem with my 03 civic, but after a couple of months the CEL light came on claiming a bad bank 1 O2 sensor. I am not sure if that was the actual cause, because I found out later that I had a bad head gasket, which also had the same symptoms, but with a CEL for misfires. I also heard the throttle body in these cars can get sticky.

I just wish whatever was breaking would just break! (of course at a time and location which is convenient for me!) What’s the cure for a sticky throttle body? Carb cleaner to the outside of the assembly? Carb cleaner to the inside? If so, what’s the best way in?

There are a number of possibilities here including but not limited to old sparkplugs, poor compression, and a flakey temperature sensor. Even though you have no CEL, it might be good to check the ECU for stored codes. Most parts stores will do this for free.

A sticky throttle body generally requires washing the TB out well with a solvent. There are TB cleaners available at the parts store.

If you had a sticky throttle body, you would feel it if your car is still a cable throttle system and not a throttle by wire system. By feel it I mean that the gas pedals would stick as you first press on it, then suddenly let go. It will not cause the symptoms you are experiencing though.

Could be temp related. The computer riches up the mixture to help motor warm up faster and ur computer may think the car is still cold and it keeps the mixture rich but the motor is actually warm? Could be a coolant temp sensor.

Thanks for all the great comments. I think your willingness to assist scared off the problem! It hasn’t happened for a day or so now… But I will say that it ‘feels’ like a sensor beginning to flake out. When it happens, it always occurs as the car is warming from cold. It has never, ever happened any other time. And I’ll say it again: I just wish whatever it is would break (at an oppotune time, and be convenient, cheap, easy to fix). That’s not asking for too much!

Thanks for the follow up post. I wish all problems were thios easy to chase away.

Happy motoriing

OK, why not… it just did it again. This time I pressed in the clutch and slammed the pedal down… The engine roared. However, if I slightly pressed down on the pedal (to drive like a sane person), the engine sputters. Clutch in, pedal to the floor, it revs fine. Then about 20 sec after it started it was gone… No check engine light (although I may hit a parts store to borrow a code reader this weekend…). I guess I can always drive pedal to the floor for 20 sec every now and then. That’s one way to spice up life real good!

Update: Yesterday on the drive home the check engine light came on! Oddly, on the way to the car part store, the check engine light switched off… Nice try ‘problem’, but you forgot the codes are stored! P0138 Bank1 Sensor2. The auto store quoted my ~$50 for the part. Anyone care to rate the difficultly of the repair? I remember dealing with the O2 sensor on out CRV was a real pain (the unclipping it from the inside part…). Any ‘heads up’ advice for this repair?
Thanks,
j

Downstream O2 Sensor Replaced. Should know in the next few days if this solved the problem.

electronics failures can be very temperature sensative. since it does fine in nuetral, i would suspect a bad ignition coil, usually the igniters are either working or dead, but a coil can fail depending on temp. or load.

Well, it has been a few days of both warm (60s) and cold (20-30s) here in Buffalo. In 15 or 20 car trips, the problem has reoccurred exactly once. Thus the frequency has dropped considerably, but the fact that it happened makes me think it wasn’t entirely the O2 sensor. Ignition coil is certainly a possibility, but the regularity with which the problem occurs (in terms of happening in between the transition from warm to cold) still makes me think it’s a sensor, perhaps the other O2 sensor… Regardless, the problem is greatly diminished, so I’ll count this as a win of sorts. Should I make more progress on diagnosis and/or repair, I’ll post here!

Live data scanners are available for about $100 and scanning software with an interface for a lap top is available for less than $30. One of those might help get to the bottom of your problem.

It just happened again, so it appears the problem is better, but not gone. And I’d really like to avoid dropping $150 to analyze the problem, but seems more and more likely this is the way to go. Anyone have a recommendation for a live data scanner? (Perhaps I’ll start a new post…)
Thanks,
j