jeff_is_sexy

I just had my optispark replaced at GM. The car had died all of a sudden and I had to have it towed there, they diagnosed it and replaced the opti, belt, and plugs.

Now that I got it back it makes a sort of weird, sharp noise right when you start it up, and it idles okay cold. When it warms up it gets down to 600rpm when braking at a stoplight in drive. Put it in neutral it gets to about 800-900rpm. It doesn't feel rough, and doesn't die.

When you get going, every once in a while it hesitates when you coast then get back on the gas, and even more rarely it does it if you nail the gas. It doesn't seem to have lost any power though.

I paid $1500 for the opti replacement ($700 for a new opti! Don't they know what eBay is!?) when I could have done it myself and in less time. I want it to run good, but if I take it back in there I'll get charged up the *** again. The details are in the sig; it's an A4.

mrmint69

Gm replacement is around 300.00 for the opti. The job is 3-5 hours of work. The price is high but not unusually for a dealership. You can only go forward from here. It could just take the car a few miles to relearn everything from the battery being disconneted. If the car ran good right before i can't think of anything they did wrong. The hardest part about the job is the water pump has to come off and the plugs suck, otherwise it is just time consuming. I had a pain with the gear on the pump and had to replace it.

jeff_is_sexy

I know that the GM replacement is supposed to be 300 bucks, but on the sheet it says $674.14 for the Optispark. Spark plugs were 8 bucks apiece! Total labor was $622.

That's not what I'm worried about though, that's all said and done. I need some suggestions as to what may be wrong now.

TobyZ28

Your idle and neutral speeds are normal for an A4. About 550 is the "desired idle" the computer is after when warmed up. When cold, depending how cold the engine is idle usually start up around 1100 or so and slowly works back down once the engine temp gets to normal.

CamaroRacing12

good, i was worried about the same thing as this guy was lol

mrmint69

There is a reset procedure for the IAC system:

http://shbox.com/1/4th_gen_tech2.html#iac_reset
Give this a try.