96 vortec 350 slow rev, no power and fouling plugs
 

i have a 96 3/4ton pickup with the vortec 350... it has had a new fuel pump new fuel filter. new distribitor new plugs and wires and what i could see new oxygen censors in it and its straight piped so no the cat isnt plugged... i tried a different computer and thats not the problem.. it starts up and runs great and will idle for days and revs fine till about 2 grand then is slow and makes no power like it should.. it takes about a 1/8 mile to get to 40mph.. it wont run for crap with the MAS off it and once you plug it back in it idles and runs about right to 2 grand. i bought the truck like it is from a budy and he said when they put it on the computer it showed a whole list of bad sensors that couldnt possibly be bad... the truck has 286k on it so its seen better days but i cant admagin the motor being original and it all sounds good at idle.. it dont seem to pop or miss fire when reving it up it just seems to rev slow as hell and not maken the power and after so long it fouls the plugs

its got me damn near stumped.. almost puttin my money on the spider injectors but im not for sure.. what all do you guys think??

Welcome to the forum, the codes would help figure this out if you have them, possibly a bad knock sensor(s) not allowing your timing to advance. but it could be a wide range of other things as well.

I think it's a matter of ruling things out...make a list of everything that shows up in codes and eliminate one at a time. Did you check fuel pressure? Was the new computer flashed by a dealer ? I have a 96 , 305 ci. You are correct the MAS needs to be hooked up. Did you clean the MAS. Is the dist. in correctly? I would start over with the simple things and progress to the harder things. It does'nt seem possible to me (IMHO ) that the complete spyder is bad. I had one bad poppet valve and I did finally up date to the newer spyder system (Amazon has the best price )

it puts out 50 to 55psi of fuel pressure when cranking over.. well its not fouling plugs so it seems as i thought from what the previous owner told me it did... i thought it had the plugs fouled out because i parked it and then next day went to start it and it wouldnt run at all so i figured it fouled them out as the guy told me it liked to do.. but tonight i put all new plugs in and it still wont fire now.. i can dump gas in it and it will fire up and run till it burns it up then dies.. it has 4 oxigen sensors and they all seem new.. they hollowed out the cats after i cut one off hopen to find a easy fix but they have both been hollowed out... i took my computer off and put it on my budys 97 and it fired his up and ran like a champ.. i cant admagin it being the MASS since it dont run at all now... i dont understand it.. i moved it and drove it up and down the ally and drive way about 5 times that day and started it atleast 10 times or more and then when i park it and come back to it it wont run anymore.. that was the first day i owned it to so that kinda leaves me in a wonder about things too.. i bought a cts sensor and the sensor that goes after the MASS because thought that could mess with it when it was running at idle trying to rev but now it wont even do that.. its not getting fuel clearly so something is telling it not to..

crank sensor?? or any other idea's..
i was going to haul it up town to a local shop and have a complete scan put on it but it dont even run to really even do that now

Hmmmm. I know it sounds too simple to be true but did you check for water in the fuel or just plain old stale gas? I have never had any luck trying to reuse gas fouled plugs. If the plugs are dry you have a fuel delivery problem ,if they are wet it's something in the ign. system. If you can post the codes I'm sure someone on this forum can help you figure this out.

Charlie

Charlie

no that gas is fine it doesnt smell stale to me or anything.. when i took the spark plugs out from when it had been ran before when i changed them the whole drivers side bank was black and had some crap on them almost just like the CAT was pluged but its hollowed out so i know thats not the problem and for sure not the problem since it dont run at all now..
the crank sensor is almost what im guesin because if that aint reading then it aint telling the computer to send fuel and it seems to not be getting fuel at all.. i gota get it back running then ill go back to the original problem or maybe im lucky its all one problem and quit all together..
its got me almost stumped but it has to be something dumb

I had the exact same problem in a van I used to own when I was stationed in NC. It ended up being an ECU/ECM wire that had rubbed bare and was touching the fender. This might help and it might not but as soon as I repaired that wire it was back to running normal

ill look her over but im having doubts that it could be that simple of a fix with my luck..

How about an update...What did you find if anything conclusive?

Charlie