i am completely stumped. i did a tune up on my 95 suburban. it included plugs,
plug wires, cap, rotor, and coil. and now, the truck is misfiring and running really
rough. i have checked the firing order, plug gap, tested all wires for spark, and
tested all plugs as well. from what i can tell, all is good. i've done many tuneups in
the past, but this is the first on this vehicle. it ran fine before, i just figured id tune
it up before a road trip. if anyone has any suggestions, that would be great
could be a bad set of plug wires cracked dis cap,or a cracked spark plug but i suspect a crossed plug wire.
i've checked the firing order multiple times. all parts are new. i've got spark in each wire when i pulled them out and tested them one by one. i'm thinking cracked boot or plug insulator. or maybe over gapped plugs.
over gaped plugs wont do this,plugs will be cracked inside,not visable on outside.remberer new parts can be bad,i do belive you have a arking problem.tell you a easy find,im guessing its dark where you are at,go out raise hood crank see if you can see a light show from plug wires,will look like lighting,if your under hood light is on unplug it.
check timing.. if its off just a hair the plugs could be firing prematurely
i havn't removed or even loosened the distributor, but it does seem to be idling low, like the timing is retarded. i am also going to try putting the old plugs back in just to see if it helps. because, like i said, i have spark fomr every wire, in every cylinder. i pulled each plug and wire out individually and tested them with the new plugs. they are working fine. but when they're bolted in, it misfires. if my boot is cracked, they could be arcing to the block. so if putting old plugs back doesnt work, im gonna try a new set of wires
I agree with andrew some of those older chevys I have seen the distbributor move without being loosend. Plus its one quick thing to eliminate..
well hey, turns out it was one bad plug wire. that was all. i really need to invest in a multi-meter so i can check for that shit at home. anyway, that part is good now, but now there is a small hint of the engine surging when it drives. not bad, but noticeable. im gonna change the fuel filter tomorrow and add some lucas fuel system cleaner. thanx to everyone for all of their advice
does the car have a tachometer? usually bad wires will make the tach needle jump at idle.
yeah, it has a tach, but its an older chevy, and like alot of older chevy, all the gages fluxuate anyway. some electrical issues in the dash. all the gages typically wave back and forth anyway. but the truck isn't misfirin anymore. got a new set of wires and all is good.
Check the Crankshaft Position sensor and Cam sensor if they are bad the engine goes to base timing or "limp home" mode and will randomly fire the spark plugs to keep the engine runing. Theser sensors could be your problem
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