Poor acceleration

I drive an 89 civic 1.5L. 245,000 miles. The car was running fine, then one day I was leaving work it developed a stumble on acceleration. The car still runs fine when its cold, but at normal temps, from idle to 3000 rpm it stumbles/hesitates. Above 3000 RPM, no problem. There are no codes/no check engine light.

I've run a tank of injector cleaner through it with no change. The really strange thing to me is that it's fine cold then the problem comes when it's warm. I've seen similar posts but the problem seems to occur when the car is cold.

Any help is appreciated.

Maybe check your plugs :dunno:

timing could have jumped a tooth too...

could be anyone of these things:
vacumn leak
O2 sensor
coil
ignitor
wires
Ground(s)
water/air temp sensor
timing to advanced
Clogged cat

but im guessing Ignitor. check the things you can first b4 going and just replacing parts. Can get expensive and may still have problem. vacumn leaks and gorund(s) should be checked. I had the same problem you do.

If you find problem let us know what it was.

GL

Check your plugs. Same thing happened to me. stopped at a light, started to idle rough. Turned out one of my plug wires popped up in the valve cover! Push down on all your spark plug wires going into valve cover and onto your cap.

thanks for the ideas. Im going to work on it this week. I'll let you know what I find

I hate to admit this...but it was a sparkplug! The plug in number four cylinder was missing that little piece of metal that the spark jumps across the gap to. The surprising thing to me is that the car idled fine, ran fine cold, ran fine above 3000 RPM. Oh well, thanks for the help!

It happens to the best of us (and to the worst of us=me). Though that doesn't sound too good that part of the plug is gone. Probably means it's in your engine somewhere.

Thanks for your input and ideas. I had the day of today so I spent some time at a salvage yard that had my throttle position sensor on a vehicle.
Bought it and put it on right there and took it for a 2 mile ride and just as it came up to temp, same thing. they were nice enought to go out and pull another and damn if it didn't do it again. Then talked to the owner Jeff Baylow at Baylow's Lester Prairie, MN and he sugested maybe computor and sure enough after giving them back both Thottle body's and throwing in the computor my son and I kept our fingers crossed and it worked plus saved $25 Thottle body was a $100,putor $75. I thanked them and tipped the yard boy a couple bucks and now I can start saving some big $$'s on my fuel bill I've already got 175 miles on a 1/3 of tank of gas going to fill up in the morning to see how well it's working.
Thanks for your input.
Tracy

also have the valves checked for adjustment, i know my car was doing that, running like crap till about 3k then it would go fine, the valves were out of adjustment

My car barely ever makes it to 3k I can be going 80 at 2.6k Just filled her up today 44 MPG yahoo I can park the truck and save a few bucks now that she's running thanks for the input I will be checking valves as soon as I get a chance.