lumina shuddering

[meuhus]

my lumina is now shuddering

it seems to be worse around 1500 rpm
it only happens when car is in od or d and with converter
locked

i just recently changed injectors (reconditioned)
the cars has around 200,000 mile
after injectors were changed
the car ran great idled great no missing
then one of the injectors failed
changed it
seemed ok (but still kind of missed)
then i noticed the spark plug wires were bad (arcing to the motor)
so i changed those
then i noticed the new wires were arcing from the boot that goes around plug to the motor
i lubed up the front three and moved the boots down
have to do the back yet
i know this could be at least part of my problem
i think i also have a little vac leak possibly (at the plenum gaskets)
but could this cause the car (motor) to shake pretty bad once and a while its not idling like it was is low now around 400 to 500
it was idling around 750 and not missing (with the fresh injectors)
the fuel pump has been recently changed as well as filter
new ignition mod
2 new coils
new iac motor
new knock sensor
new tps
new crank sensor

oh i do not have any check engine light on or codes
other wires look good
tach also seems to jump with the miss sometimes

thanks for any help

it is a 91 with a 3.1
4 speed auto

[maxwedge]

A shudder in lock up is usually a bad lock up convertor or an engine stumble /misfire. Scan it and make sure fuel trims are normal and o'2 activity is good. remember an ign. misfire is worse when in lock up under slight load, cheap wires can haunt you here.

[meuhus]

Originally Posted by maxwedge

A shudder in lock up is usually a bad lock up convertor or an engine stumble /misfire. Scan it and make sure fuel trims are normal and o'2 activity is good. remember an ign. misfire is worse when in lock up under slight load, cheap wires can haunt you here.

who makes the best wires
my olds cutlass ciera does the same
the wires are arcing to block but not miss firing

the new wires are leaking on my lumina
and the old ones were too
before injectors were bad too
i'm sure but was not missing
when all injectors were fresh

[maxwedge]

Napa has a premium wire set so does Delco, these ign sytems can produce up to 80k volts at max demand quality wires are a must.

[meuhus]

Originally Posted by maxwedge

Napa has a premium wire set so does Delco, these ign sytems can produce up to 80k volts at max demand quality wires are a must.

why would autozone not now that or make a product and sell it
that wasn't up to par
basterds

[maxwedge]

Autozone sells the cheapest parts they can secure, that is their business they may have a premium set of wires but you must ask for them specifically. You expect their counter clerks to be technically up on these issues, if they were that sharp they wouldn't be working at AZ! Remember these engines should also be running OE style AC plats, if not additional stress can be put on all the ignition components.

[meuhus]

Originally Posted by maxwedge

Autozone sells the cheapest parts they can secure, that is their business they may have a premium set of wires but you must ask for them specifically. You expect their counter clerks to be technically up on these issues, if they were that sharp they wouldn't be working at AZ! Remember these engines should also be running OE style AC plats, if not additional stress can be put on all the ignition components.

well
the car had champion plugs in it
before i changed them to regular ac delcos
but i didn't put in platnums
the car ran fine untill injector went bad
i just talked to az and they can get me a new set of wires for free
double silicon
or i could up grade to the bosch set
i didn't get the cheepest wires but figuered middle of the road was the best bet
i guess i was wrong

i have the double silicon on there now
will see about getting the bosch set i guess

[maxwedge]

25-35k on non plats will be your plug life.