HIGH IDLE ISSUE AND INTERMITTANT SHIFTING CAUSE IAC, TPS?

1999 Buick Century

Tiny

dlvaughn1963

October, 13, 2012 AT 2:13 PM

Here's the situation at this point
I have replaced all 6 plugs
four broke at the ceramics, two had worn tips but suspect bad gap and just old plugs. They had Autolite 606 plugs.
Got the new plugs in, starts and idles fine, BUT, still have surging and misfiring. When the car is running and I'm driving for about 1/4 mile it runs horribly, but after that, the car settles and runs fine. This happens anytime the car is shut down and restarted. Any other suggestions? I have checked the coils, but they seem to be producing good spark. I will take the coil wire caps off and look at the spark in order and see if they seem to be weak at the cap. Then possibly look into either coil, or bad ICM.

Tiny

dlvaughn1963

October, 13, 2012 AT 3:02 PM

I'll keep u posted but looks like bad wires.#5 wire when I pull it off the coil does not surge. So will know in a bit.

Tiny

saturntech9

October, 13, 2012 AT 3:55 PM

When you did the heads you never changed the spark plugs shame on you especially when you described what they look like. Also keep me posted on ho it works out with the plug wires.I would remove the egr valve clean it and with the egr valve off start the engine for a few seconds. The engine should race and you should hear a loud exhaust leak?That helps blow the loose carbon out that can can make the new egr valve stick.

Tiny

dlvaughn1963

October, 13, 2012 AT 6:01 PM

You must be talking about the the guy doing the engine overhaul. I never did such a thing. : ). I got the wires hope to give you an update tomorrow.

Tiny

saturntech9

October, 13, 2012 AT 6:50 PM

This is exactly why I usually make people start there own questions it just gets way to confusing who did what who iam actually talking to etc. So greghoward please start a question for your car. Start it off by saying this one is for saturntech9 and they will leave the question for. That way I can continue helping you nothing personal its just hard enough helping someone over the internet fix there car but then two different people on the same question that's too much.

Tiny

dlvaughn1963

October, 14, 2012 AT 11:56 PM

Replaced wires seems to be working. Have only had two hiccups in 50 miles of driving, and 8 starts and stops. Looks as if the reset of the wiring of the ignition control module has this possibly (the second problem) for the moment fixed. There's great acceleration and the car sips fuel instead of gulping. I've not seen an issue with the O2 sensor. All is good for now.

Tiny

saturntech9

October, 15, 2012 AT 3:11 AM

Thats what we like to hear keep me posted on how it works out.

Tiny

dlvaughn1963

October, 16, 2012 AT 1:38 AM

Ok now I'm stumped.
Ignition system everything has been changed but the ICM. Plugs, wires, coils. Still misfires but is intermittently. Guess on my next few days I will check to make sure it pulses.I did check the contacts on the pink wire.I get 12 volts, and each coil when I pulled them off, I checked for voltage on the contact pins, and they do get 12 volts. The only thing I did not check is the pulse. With a led light. Three fuel injectors I checked on the forward side is pumping fuel. The misfire is very random any clues?

Tiny

saturntech9

October, 16, 2012 AT 1:58 AM

Possibly a dirty injector I have seen them cause very random missfires.

Tiny

dlvaughn1963

October, 16, 2012 AT 2:49 AM

So what I need to put some fuel cleaner in the tank?

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