first of all hello everyone this is my first post and i could really use some help on this. i have a 97 gmc 1500 as my work truck, the problems started when i had my truck jacked up to change the ball joints. it was on jack stands all weekend then when i let it down it was hard to start then ran bad and had a miss at around 55 mph and 70 mph while i was crusing. it does fine while accelerating. i have since changed the fuel filter, plugs and wires whole distibutor assembly, coil, cam posistion sensor,egr valve,and a new fuel pump with another new filter. i also ran some seafoam through the vacuem line and crank case, i plan on running some through the gas also. the cel is on so i had advance auto scan it and it came back with bad maf sensor so i changed it, bad cam position sensor so i changed it. also evap system malfuntion so i changed the egr valve. the weird thing is the cel light will not go off, even when advanced reset it as soon as i crank the truck its like it never went off. please help i'm at the end of my rope.

 

you might get an answer if you go to the silverado side of the forum. The sierra forum seems to be coasting as of now.

 

I would try something simple first...diconnect the battery for a few minutes and let the ECM reset. There is no way all those sensors went bad by just jacking up the truck. The late 90's truck are famous for a few problems. You have already covered the fuel pump, the other 2 that I have experienced on ALOT of them are the spider injection and the intake gasket. The spider injection sounds more like your issue. It will make it hard to start when cold and will give you some issues while cruising. The only thing that is strange is you emply your truck was fine before jacking it up. Did you pinch or damage something with the jack or jack stands? I would start there. What codes do you currently have?