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| Intermittent miss | |
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| Tweet Topic Started: Sep 18 2011, 03:49 PM (2,569 Views) | |
| Maas562 | Sep 18 2011, 03:49 PM Post #1 |
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:)
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I have a 95 3/5. Just recently it's been giving me problems. Only after sitting for a period of time after start up it misses really bad under power. If I cruise really slowly up to speed it's fine but if there is any load put on the motor it misses terribly. After a few miles or once the motor warms up a bit it goes away completely. I'm stumped, any ideas? |
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| Old Man | Sep 18 2011, 05:01 PM Post #2 |
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I know very little about this but it sounds like your fuel control system thinks the engine is warm at all times, and does not give it the extra fuel a cold start requires. Just guessing here--stand by someone who knows will check in .............. Edited by Old Man, Sep 18 2011, 05:02 PM.
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| Deleted User | Sep 18 2011, 05:29 PM Post #3 |
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Deleted User
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Your valve lifters are gummed up. This will lead to more serious problems, like burned exhaust valves. The quick fix to try is 8 ounces of Marvel Mystery Oil with a fresh oil change. Maybe. Anything else requires surgery. Please do check the engine compression and idle vacuum. The compressions should all be close to the same, and the vacuum gauge reads steady. How many miles on the engine? |
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| JellyBeanDriver | Sep 18 2011, 05:57 PM Post #4 |
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Sounds like my Metro. If I let it sit for a week, when I start it up one or more of the cylinders floods and I have to be careful to keep the RPM's up until it clears otherwise it could stall and not start. Don't think my injector is leaking, but I don't know of any other reason why it would do this. |
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| Maas562 | Sep 18 2011, 06:07 PM Post #5 |
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:)
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Geo Glenn theres 163,000 miles on the motor |
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| JellyBeanDriver | Sep 18 2011, 06:14 PM Post #6 |
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How much time does your car need to sit for this condition to occur? How's your ignition system? Good cap, wires, plugs? I had an stumble during low RPM acceleration that was ignition related and went away with a new set of plugs. |
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| Maas562 | Sep 18 2011, 06:36 PM Post #7 |
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:)
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Well I used the car all day yesterday and then it sat over night until about 4pm today. I started it up to leave pulled out of the driveway and it happened as I started to accelerate. As for the other times it's happened basically the same amount of time. Just sitting over night. It doesn't happen all the time either. I did it a few weeks ago and then it just happened again today. Wires and plugs are all new about 2000 miles ago. Cap I have no clue if the past owner changed it or not. |
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| Spock | Sep 18 2011, 06:41 PM Post #8 |
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Live Long and Prosper.
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Does it backfire? |
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| Maas562 | Sep 18 2011, 06:55 PM Post #9 |
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:)
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Not that I noticed, just starts to chug and jerk pretty bad if I keep trying to accelerate |
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| Spock | Sep 18 2011, 07:20 PM Post #10 |
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Live Long and Prosper.
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I've seen Plugs fail right out of the box. 2000 miles might be the end of the road for this particular set. Go ahead and change the Plugs, cap, rotor and wires. They're dirt cheap and they will eliminate a troubleshooting headache. Want me to tell you the story about how I tore down the carb in my motorcycle twice because I was convinced my plugs were brand new and couldn't possibly be bad? GeoGlenn's suggestion about the lifters is more likely your problem. Try his suggestion about using the marvel mystery oil with a fresh oil change. I have an angry lifter in my Geo too. It presents very similar symptoms as your car. I just deal with it cause it doesn't last that long or bother me that much. After you've tried all that, if you still have a problem, report back and we'll continue troubleshooting. Edit: Oh yeah, these motors are very prone to roasting exhaust valves, as you may well be aware. While you are tinkering, do try to get some compression numbers so that you can eliminate that as a possible cause of your problems. Good Luck!! ---Rob Edited by Spock, Sep 18 2011, 07:23 PM.
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| Maas562 | Sep 18 2011, 07:30 PM Post #11 |
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:)
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Thanks for all the help. I did just go out and clean up the contacts on the cap and rotor. Took her out for a spin and the problem was gone. Whether that actually fixed it or it is just being stubborn I guess we will see. I'll throw a new cap and rotor on and get some compression numbers as well. Thanks again. |
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| JellyBeanDriver | Sep 18 2011, 08:37 PM Post #12 |
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What brand and type plugs are you running? |
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| Maas562 | Sep 21 2011, 10:38 PM Post #13 |
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:)
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I'll check the plugs tomorrow but the miss did come back twice after I have cleaned the contacts in the distributor. I did not put a new one on yet. Both times have been after running for some time and only lasted a few seconds. A bit of a change from when it did it on a cold start in the past. Also every time I have noticed it happening it has been damp, meaning either during rain or after rain. Not sure if that makes a difference. |
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| Maas562 | Sep 22 2011, 05:39 PM Post #14 |
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:)
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Plugs are champion RN12YC |
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| Spock | Sep 22 2011, 06:43 PM Post #15 |
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Live Long and Prosper.
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Here's an old school mechanics trick I've used in the past with great success: (do this at night) Spray a little water on the spark plug wires while the car is off. Then, start the engine. If you notice sparking and arcing from the spark plug wires, they're shot. If not, dry them off and move on. On the other hand, If it has been a while (more than a year) since you have replaced the spark plug wires, distributor cap, rotor and spark plugs, replace them anyway. It's cheap and easy to do and it'll eliminate those items from your troubleshooting. Good Luck, Rob |
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