88 chevy runs bad

i have an 88 chevy k2500 barley runs backfires through throllte body and when i disconnect timming connector it runs much better i replaced map sensor/ egr valve/ecm/esp module and still no luck i appreciate any help i
can get thanks
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helly wrote:

Timing CHAIN
Computer

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And to check the timing chain without taking it all apart...
Remove cap. Rotate engine 1/2 turn or more BACKWARDS until the timing mark is around ten degrees. Place clothes pin (etc) on distributor body by the trailing edge of rotor. Slowly rotate it forward until the rotor JUST moves (the pin above is just so you can see this easier). If you get more than about 8-10 degrees of movement, there's a good chance it's stretched and jumped.
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i checked the timing chain i get about 6 degrees of movement is that enough to jump
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helly wrote:

to me on my 1995.
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hello my friend at work just ran into same thing on a c1500 4.3, changed all sensors,check and rechecked timing, put in new fuel regular, checked fuel pressure and it was in spec but on the lower end, put in new fuel pump and cured the problem. hope it hopes, ps i think fuel pressure should be between 8 and 14psi but could be wrong. so double check specs.

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