93 Suburban 5.7L TBI, rough idle loss of power

93burbin

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OK i have changed the O2,tps,egr,egr valve,Idle air control valve, 2 new injectors, fuel filter and pump and screen. spark plugs and wires. Some times it fires up and runs good others times I'm lucky to get 35mph to mat. I have noticed when the engine running at a idle with air filter off it starts to suck a lot of vacuum thru the TBI where the idle air flow sensor is. then it starts running rough and wants to die. I'm at a loss and dont know what else to check. I have limited skills and tools. please help
 
well i will say with what you spent on throwing parts at it you could of just had it fixed at a shop. To fix your problem you will need a scan tool and know how to read a data stream and know what it means. If i were you i would take it to a shop and have it diag and then take it home and fix it my self. Good luck
 
It,s been to the shop and they have scanned it and it is not throwing any codes. Last time it was in the shop it cost me almost 400 bucks and they said it had water in the tank. they replaced the fuel pump and screen and filter and cleaned the tank. Then when i went to pick it up they informed me the tank was fairly clean and not much water. It ran good after picking it up for about 3 days them back to this. I was looking it over my self and seen 1 injector was not spraying good so i replaced both injectors ran good but not like it used to. some days it runs great other days not so good. It has been to the shop several times cost more each time in the shop than what it cost me to replace all the little parts.
 
well then it's time for a new shop. The shop your going to now must be parts replacers. Also your tk is OBD 1 and just becaues there no codes does not mean all is well. It needs to be driven by someone that knows how to read a data stream and they will fix your tk.

OBD 1 has very wide fail rate on all there sensors. For example your coolant temp sensor could read 45 degrees below zero and never throw a code. as where OBD 2 would becaues OBD 2 would also look at the air temp sensor and know the coolant temp is wrong and set a code and turn the light on.

really you just need a good tech to look at it.
 


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