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| jimmers | Still need help, car stumbles! | ||
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Senior Guru
 
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Over the past few weeks my car has been in and out of the garage trying to fix my stumble problem, but it keeps returning. When I accelerate the car will stumble most of the time when hot or cold. I've replaced the plugs, wires, coil, cap, rotor, ignition module, fuel pump, and filters. I've tested the fuel pressure when the problem occurs and it stays rock solid. I'm all out of ideas!! The cats are removed so they can't be plugged. Is it possible to be a plugged muffler or somthing? IAC and TPS were replaced last year. Help!!
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Posted on: 2008/7/25 13:06
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| Qack | Re: Still need help, car stumbles! | ||
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What engine do you have?
Added: Aha, it's a '90, so an L98. Can't help on specifics as mine is a 94. Have you checked the injectors for leaks or clogging? How about voltage to the various things electric that are involved? Or a bad ground? It could be an internally-failed muffler -- and have you checked for any potatoes in your tail pipe? |
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Posted on: 2008/7/25 13:33
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| DaleD | Re: Still need help, car stumbles! | ||
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Wow, that's really frustrating. I'm not a mechanic so I can only make simple guesses. I do know it's air-fuel-spark. Sounds like you have spark and fuel covered.
MAF? Another guess that might be stupid, but what the heck, I'll offer it: I just had my head gaskets fail. Before it failed, I had a slight miss at idle. Check your exhaust, make sure it's not too smokey. |
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Posted on: 2008/7/25 13:36
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| jimmers | Re: Still need help, car stumbles! | ||
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Senior Guru
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The engine was rebuilt last year so the injectors are brand new. I don't have a MAF sensor, as its a speed density car. I could run a can of injector cleaner through it and see if it helps. The car doesnt surgre at all so I don't think its a vacuum leak.
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Posted on: 2008/7/25 13:54
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| Woodstock | Re: Still need help, car stumbles! | ||
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Sounds like fuel injectors. Measure the resistance cold and hot, should be about 16-17 ohms.
edit: when it happens unplug the EST wire, if it runs better on the ignition module it could be the pickup coil or ECM. |
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Posted on: 2008/7/25 13:56
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| red_johnny | Re: Still need help, car stumbles! | ||
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On Sabbatical
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I would think to start looking twards the injectors. Sounds to me its fuel related, could even be running too rich? When its running go behind the car and see if you smell gas or a gassy smell. That could point to it running rich. Could also be running lean as well though.
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Posted on: 2008/7/25 14:26
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| jimmers | Re: Still need help, car stumbles! | ||
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Quote:
Thanks, I'll give that a try later tonight. |
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Posted on: 2008/7/25 19:06
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| jimmers | Re: Still need help, car stumbles! | ||
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Quote:
Ever since the engine was rebuilt you can smell gas behind the car. The cats and air pump are removed but it doesn't smell any worse then it has in the past. The car was tuned last year after the engine rebuild. Could a tune become bad? |
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Posted on: 2008/7/25 19:10
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| biggrizzly | Re: Still need help, car stumbles! | ||
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This is a long shot... but several years ago I bought some bad gas from a station in South Carolina. I could tell almost the moment I left the station it was bad. It did the same thing with hesitation as yours. After I returned home I took it to a friends garage and we drained the rest of the fuel, put good clean fuel in the tank and run some injector cleaner through it. I don't know what was in that gas, but my car did not like it at all.
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Posted on: 2008/7/25 19:38
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| jimmers | Re: Still need help, car stumbles! | ||
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I thought about the gas also. The tank is almost empty so I'm going to fill up tonoght. I hope this will fix my problem, but I doubt it.
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Posted on: 2008/7/25 22:41
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| Midnight85 | Re: Still need help, car stumbles! | ||
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Have you checked the tps setting since it was installed? Give it a check and if it is set like it should be it'll be set at .54 volts with the throttle closed. If it isn't, set it to that spec. If it is already set there then bump it a bit higher, say .56 to .58.
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Posted on: 2008/7/26 1:35
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| jimmers | Re: Still need help, car stumbles! | ||
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Well it turns out my disbributor bolt was loose causing the disbributor to move around. I tightened it back down and the problem seems to be gone. When I set the timing the disbributor would only go so far one way before stopping. Is this normal? I thought it should turn both ways equally?
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Posted on: 2008/7/26 5:30
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| jimmers | Re: Still need help, car stumbles! | ||
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Well I fixed the distributor. It turns out the fork was barely on. I set the timing and all was well, for a bit! The car started to do it again after a short drive. I took it back home and checked the timing. The timing hadn't moved. I went to go drive it to work today, but it was much worse. Any ideas as to what is going on? How can it get worse just sitting in the driveway?
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Posted on: 2008/7/28 13:02
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| biggrizzly | Re: Still need help, car stumbles! | ||
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Did you say that you replaced the ignition control module? I think this can be removed and tested. I have had iginition control modules on more than one car be bad before and cause driveability problems. Also, have you checked the coil?
EDIT - I just re-read the post and saw that you already put new components on. Sorry - I'll keep thinkin' about it for you. Good Luck |
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Posted on: 2008/7/28 15:48
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| Randy93 | Re: Still need help, car stumbles! | ||
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Have you checked the vacuum lines for leaks?
How did you set your base timing? Go to a garage and have them do a emmisions check, that will tell you if you are rich or lean. |
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Posted on: 2008/7/30 16:56
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| jimmers | Re: Still need help, car stumbles! | ||
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Quote:
I checked for a vacuum leak but didn't find any. I'm not ruling that out because we all know how hard they are to find. I unplugged the est wire, set the timing to 6 BTDC, then plugged it back in. I'm trying to get my laptop to work with my car again so I can datalog and see exactly what's going on. I figure if it was running rich though, I would get an error code about an 02 sensor. |
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Posted on: 2008/7/31 0:07
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| Qack | Re: Still need help, car stumbles! | ||
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Quote:
Have you checked your injectors yet like Woodstock suggested? |
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Posted on: 2008/7/31 17:26
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| jimmers | Re: Still need help, car stumbles! | ||
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Yes I have. All injectors ohmed at 15.2. |
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Posted on: 2008/7/31 20:20
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| jim420 | Re: Still need help, car stumbles! | ||
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If you are running a paper fuel filter check it and replace it any amount of water in gas even a drop will not pass through element and will not let enough fuel to pass to feed that hungry engine just a thought
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Posted on: 2008/7/31 21:29
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| Mekanic | Re: Still need help, car stumbles! | ||
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Quote:
hot or cold? Sounds very injectory to me |
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Posted on: 2008/7/31 23:28
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