Here we go again with random misfire

[mkingan]

So this tahoe is driving me nuts. Running out of things to check. So started out crank no start, ignition and coil bad. all replaced plus new distributor, plugs wires, crankshaft position sensor. Fired right up. good. 2 months later same thing. pulling crankshaft code. Swapped it out with another. fired right back up. ran great, 3 weeks later here comes check engine light again. Multiple random misfires, got to be something internal cause every sensor or electronic piece has been replaced. timing is right on (had shop check it). fuel pressure good. Could it be that spider fuel assembly leaking? slack in the chain? i am out of ideas. need a direction to point to.

 

[Kelsda]

So this tahoe is driving me nuts. Running out of things to check. So started out crank no start, ignition and coil bad. all replaced plus new distributor, plugs wires, crankshaft position sensor. Fired right up. good. 2 months later same thing. pulling crankshaft code. Swapped it out with another. fired right back up. ran great, 3 weeks later here comes check engine light again. Multiple random misfires, got to be something internal cause every sensor or electronic piece has been replaced. timing is right on (had shop check it). fuel pressure good. Could it be that spider fuel assembly leaking? slack in the chain? i am out of ideas. need a direction to point to.

Sometimes it’s worth paying the shop for a diagnosis so your not throwing parts and money at it they can scan it like 02 sensors injectors and so on how many miles on it maybe cam is worn could be clogged cats Use carb cleaner or starting fluid check for intake leaks spray around upper and lower intake if idle goes up leak if runs like crap and gets better leak spray around vacuum lines possible broken vacuum line have a fire extinguisher near because your spraying flammable liquids on a hot idling electrical fuel burning engine take off egr clean it I had P0301 specific to cylinder one same causes 45 things to check my spider injector wasn’t firing rolled the dice 500 dollars later engine code went away if leaking bad raw fuel in oil pull dipstick take a whiff

 

[mkingan]

Sometimes it’s worth paying the shop for a diagnosis so your not throwing parts and money at it they can scan it like 02 sensors injectors and so on how many miles on it maybe cam is worn could be clogged cats Use carb cleaner or starting fluid check for intake leaks spray around upper and lower intake if idle goes up leak if runs like crap and gets better leak spray around vacuum lines possible broken vacuum line have a fire extinguisher near because your spraying flammable liquids on a hot idling electrical fuel burning engine take off egr clean it I had P0301 specific to cylinder one same causes 45 things to check my spider injector wasn’t firing rolled the dice 500 dollars later engine code went away if leaking bad raw fuel in oil pull dipstick take a whiff

its got over 200k. leaks around intake has been checked, no leaks. exhaust is new so o2 sensors. i'm thinking cam with that amout of miles. funny thing is it runs no defferent when it codes out

 

[mkingan]

i'll bet its the spider injections. ton of those go bad and they re-vamped them to fix the issue

 

[exp500]

Have the intake manifold gaskets been changed? Have you swapped spark plugs from misfiring cylinder to see if miss follows? What are fuel pressures? Also, Try to keep all your questions/diagnostics/repairs in this post so we can follow the history to better diagnose your issue(s).