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73-87 Chevy _ GMC Trucks => Suburbans => Topic started by: big burb on April 25, 2009, 09:53:39 pm
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my 91'burban is running bad. at idle its fine,rev to 3000 + and before i replaced the fuel filter it would break up .now with the new filter it does not do that.it just boggs down when driving.it also bogged before the filter but alot worse.i also cleaned the cap and rotor,that seemed to help alittle(will replace those tomorrow with new parts).anyone have any ideas what could be wrong.
i need to fix this now because or mercedes burnt up today...had an engine fire.so please lead me in the right direction, thank you.
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I'd check timing, check plugs, replace rotor and cap and wires. If still does that, it is probably a fuel problem, pump may not be at right psi--there should be some kind of guage to check fuel pump.
If that is fine, may be in the TBI. Is your "service engine soon" on?
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i would lean more to the fuel problem, try some cleaner and see were that goes but also since you said when you cleaned the cap and all it seamed to do i little better also a full tune up wont hurt
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Make sure you check the injector connectors and their wires if its a TBI!
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Check your fuel pressure and it's probably time to rebuild the tbi unit. Find the flexible hose to the return side of the fuel system and pinch it off. Then take it for a ride and see what happens.
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Had the same issue with my '88 r-20 burb with a TBI 454. pulled my air out trying to figure out what the problem was. It ended up being plug wires breaking down. checked them with a VOM and they all "ohm'd out" fine but would break down under a load. Acted like it was starving or fuel....So New ACdelco plugs, wires, cap and rotor....problem solved!
Hope that helps, good luck
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mine did the same and it was the coil going bad, weird I know because I thought if one goes bad it just stops firing but not the case with mine.