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Discussion Starter #1
ok so since ive started driving my camino after sitting in the garage for a few years im fixing all the little issues i can find. So far ive replace every noticeable vacuum hose, removed the heat riser hose and plugged off that vacuum hose opening adn closing the heat riser.

i just put 6 copper plugs in (4.3L V6) gapped them and everything. car is deffinitley running a lot better then it used to. Wires and distributer and cap look fine.

my problem is i seem to lack throttle response if i matt the throttle at 700-1000 RPM the car will choke out and sometimes stall. I have electronic TB injection and have eliminated every electrical problem from the throttle body. im guessing i have a fuel filter of fuel pump thats clogged or not pumping.

my question is in an 86 elco is that fuel filter and pump in the tank? i looked underneath without a lift or jack and couldnt find any filter outside of the tank. am i missing something here?

im 90% convinced i have a fuel delivery issue but cant find where its not delivering from....



i ordered an OBD1 to USB cable to hopefully diagnose what my pressure is in the fuel rail since i have all the software already.


but putting the diagnostics port aside, what do you think? am i right about fuel delivery?

when i replaced the plugs they looked almost perfect other then i can tell the motor has been run hot a few times. ran a tad lean but nothing serious. im just confused at to whats causing this other then fuel delivery.

im trying to avoid dropping the gas tank and tering into filters/pumps inside if theres an easier way to diagnose or fix..... HELP!
 

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Discussion Starter #2
btw the lines from tank pick up all the way to that vacuum fuel rail looked solid, so no drips, leaks or anything
 

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The 4.3 fuel filter (in line) is on the passenger side frame rail near the rear end !!
 

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If the cruck runs good at wider throttle openings it is probably not a filter or fuel delivery issue. It uses more fuel at more throttle so you would have even worse running problems. Will it hurt to change the filter - of course not. I would look harder at the throttle position sensor. The windings wear just off idle where it is used the most and the ecm doesn't know what to do with the mixture when it gets erroneous inputs. It takes almost a full open or a dead short to set a code for the TPS.
Just what I would look at form your description of the problem.
 

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look for 12 to 18 psi fuel pressure ,those have no way to check the pressure without putting a gauge inline.look for a good cone shaped fuel spray from both injectors .it should increase when you throttle it.with it idleing move the lever of the tps to see if the fuel picks up. it should make the engine stumble from the excess fuel.if not you may have a bad tps.put the est in bypass to verify base timing.make sure the est is functioning with a timing light not just a scanner.i have run across bad pressure regulators that cause your complaints.also disconnect your egr valve and plug the line to see if your egr solenoid has failed and is opening the egr valve too soon.i have a 88 tbi 4.3 blazer in the shop right now with that very problem,as soon as you throttle it the egr starts to open causeing the engine to stumble
 

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Discussion Starter #7
look for 12 to 18 psi fuel pressure ,those have no way to check the pressure without putting a gauge inline.look for a good cone shaped fuel spray from both injectors .it should increase when you throttle it.with it idleing move the lever of the tps to see if the fuel picks up. it should make the engine stumble from the excess fuel.if not you may have a bad tps.put the est in bypass to verify base timing.make sure the est is functioning with a timing light not just a scanner.i have run across bad pressure regulators that cause your complaints.also disconnect your egr valve and plug the line to see if your egr solenoid has failed and is opening the egr valve too soon.i have a 88 tbi 4.3 blazer in the shop right now with that very problem,as soon as you throttle it the egr starts to open causeing the engine to stumble
Where is the EST connector? i put a timing light to it before but someone told me you need to disconnect a vacuum hose to correctly test timing. if im correct on where the balancer is, its a real pain to see
 

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Discussion Starter #8
also any ideas on an easy way to test my TPS? or is this one of those things that will be process of elimination?
 

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Discussion Starter #9
Well im pretty sure its the fuel pump in the gas tank. was really hoping to avoid that but new filter, and i im not getting good fuel pressure in the rail. kinda makes sense because when i get to less than a quarter tank it gets worse. thanks for all the help and knowledge
 
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