engine miss/electrical?

[joeb]

saturday tinkering. 1996 STS. miss at idle. checked all plug wires. 3k ohms avg? or is it 3 ohms? did not look real close at meter. checked all injectors. 12kohms or is it 12ohms. they were all the same though. pulled all plugs. they look identical. light tan. no soot. they are not delco double platinums though. should i put in the proper plugs? only 1 yr old. whats $50 while i am at it? new intake gaskets by the way. car runs great at speed. no surging, missing or lugging. had heads off last year. timeserted block FYI. checked coils too. 5.6kohm. they were all the same. how about a new battery ground strap. the current crimp connectors look a little twisted up from pulling the motor last year. maybe i have a poor ground? $44 at the dealer.

[BuenoOffenhauser]

...... they are not delco double platinums though. should i put in the proper plugs? ....

Yup! These cars seem to do best with the Delco plugs specified for them. Some seem to get by with other brands but many don't. I've yet to see a post indicating that a miss was caused by using the correct plugs.

FWIW

YMMV

[Cadillac Jim]

The resistances should all be in kOhms except the injectors, which are probably 12 Ohms (I didn't check) -- but if the injectors are all the same and the car runs at all they are all OK.

The non-OEM plubs are almost certainly the problem, as BuenoOffenhauser says. Another principle to observe with aluminum heads and pre-lubricated boots and threads: never put an old plug back into the head. Even in the old days, a spark plug is one of those parts that, if you see it, change it.

[joeb]

i have never heard that bit of advice about plugs. i suppose if you think there is something up with the plug and you take it out, you might as well put in a new one since they are so cheap. except for ac-delco double platinum tip plugs. i had all the wires off to check the resistance. i think the 4 wires on the back head are all rearranged now. that is, different wires on different plugs. they are so close in length i do not believe it matters exactly where they go. so i started the car and went to the store and i believe it does run better. i put in the old plugs, different cylinders too. when i swapped out the intake last month, i moved all the injectors to new positions. still ran the same. i have yet to figure out if i have a suspect cylinder.

[Ranger]

i think the 4 wires on the back head are all rearranged now. that is, different wires on different plugs

.

You didn't screw up the firing order did you?

How old are those wires. Moving old wires around can cause them to misfire. It was pretty common when they where doing the fuel rail recall. mine started missing right afterwards. New A/C Delco wires cured it.

[Cadillac Jim]

My list of if-you-see-them-replace-them parts varies from the routine to the why-do-you-do-that category, and includes, but is not limited to:

• Spark plugs, Delco or not -- you get factory anti-seize and boot lube that you can't duplicate.
• Gaskets, except those explicitly designated in the FSM as re-usable such as 1995-1999 intake manifold gaskets.
• Thermostats.
• Any easily replaceable hoses that are off, excepting lifetime neoprene or silicone hoses.
• Belts, excluding nearly new serpentine belts.
• Any wear part, such as cam chain tensioner, brake pads, etc. unless they are nearly new.
• Antifreeze. If you drain it out, throw it out.
• Oil. If you drain it out, throw it out.
• Any replaceable filter or element. Oil, air, whatever.
• Oil pump.
• Water pump. If it's off, a new one goes back.
• Bulbs. New bulbs that show no blackness on the glass may be spared if they aren't handy.

Basically any regular maintenance or throw-away part doesn't get put back in my car used unless I fee sure that I can count on it just like a new part.

[joeb]

i meant to say i moved the wire from plug #1/coil#1 to plug#7/coil #7 and so on. when i start the car and back out of the garage i have my foot on the brake, i can really feel the miss than. today, it did not seem to miss at all. it seems to idle fine at stoplights now. i had gotten into the habit of shifting into neutral and taking my foot off the brake since it gave me the illusion of smoother idling. now it seems better. is it gone completely? who knows.

[Ranger]

OK, you moved the wires on the coils, but did you move the other end of the wire to the proper plug as well. If you didn't you completely screwed up the firing order. If that where the case, I suspect it would be so far out of order that it would not run.

[joeb]

i saw on horsepower tv (copyrighted) where they tested a cam with 2 cylinders that were reversed in the firing order. they picked up a good amount of hp. hmm, maybe i should try that. i had read about that years ago. i assume they had to correct the hookup at the distributor. yes, the plug wires i have now are routed to the proper plugs from the coils.