my daughters blazer seems to have a bad miss es[ecially when its wet out.
under load its not to bad but once you level off at just about any speed it misses pretty bad.

recently i changed

plugs acdelco
wires auto zone
cap auto zone
rotor

i remember a while back i was working n it and i laid my hand across the coil and got zapped . I thought new wires were in order . But now om thinking it may be the coil

anyone else have this issue

 

Ill tell ya what everyone else will tell ya.... use only delco caps and rotors.

 

update 98blazer still missing it happens under normal driving conditions . when i stomp on it runs great.

it did get worse when it rained but i have found that problem ignition coil had a small bad spot arching when wet

history when miss started
-replaced lower intake gaskets.
-replaced plugs ac delco
-replaced spider 2002 model ac delco
-replaced cap and rotor twice first auto zone parts second ac delco no change
-replaced tsat
-triple checked all the connections

what is causing this here is my train of thought

ignition timing when i did the lower intake change i marked the distributor and didn't turn over the engine at all when i put distributor back in it dropped right in no problems . do i need to retime the engine using a scanner since this has EDI timing.

do i have a problem in the egr

could i have gaped my plugs wrong

possible timing chain worn out

or should i just drive it off a cliff

there currently are no codes or engine light on

if anyone lives in muskegon mi area i would be willing to pay someone t check timing if they have a scanner

 

Is this all the time or only after engine up to OP temp?

Here are well known causes of low-load missfires:
Bosch Plats or Plugs gapped wrong or one range too cold.

MAF dirty - warm engine, stop engine, unplug MAF harness connector.. drive test.

egr pintle dirty -this causes vcm to think engine is running richer than it is. Result - too lean at cruise. No you cant see that looking at trim or O2 switching with a scanner

Cheap plug wires. Often right out of the box, especially from AZ. Been there.
NEVER THROW AWAY old wires unless they are really bad, until your engine runs great.

low compression

More I read on here. more I believe the vcm only recognizes crossfires, not failure to fire.

 

thanks for the reply i will check maf and plugs first. Like i said this all started after the lower intake change so i beleive it is connected t something i changed

 

ok i unplugged the maf and take it for a spin ran awesome. brang it home cleaned maf cleared code and test drove .

at this point it runs great

finally hopefully this is it.

drove about 20 miles and so far so good

thanks for the help . i never even considered the ecu was leaning out the mixture causing the misfire.

 

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