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the car is posessed....

MIke D

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It was a really nice Florida day... mid 70's, light breeze and we need to get some things done. So I am driving my parents 93 sts and that's when it happens...

Sitting at a traffic light with lite brake pressure and then the car surges forward. 1500 rpm's. SO I really have to step on the brakes. Light turns green then vrooooom off we go. Funny thing is I have not stepped on the gas yet. Then it goes away... then it is back... then it goes away... get the picture? The car just wanted to run @ 1500 rpm's for a long period of time..

Codes you ask... PO27...

So this makes me think...

1. What do I do? Get a new TPS and install it, or is it something else?

2. Could this have anything to do with their car stalling and not starting a week ago?

Here is his post explaining the problem. http://caddyinfo.ipbhost.com/index.php?showtopic=4971

Unfortunately my books are in texas and his are in boston. Any help would really be great... Thanks... Mike D

Cop didn't see it, I didn't do it!

93 STS 225,000 Miles

99 STS 111,000 Miles

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My guess is ISC and/or the Fuel Pressure Regulator may be leaking fuel. I had a simillar drivebility problem. The FPR is easy to check. Just take off the vacuum line and see if there is any gas leaking. It should be none. Car can be running and in Park. Also maybe you just need to adjust the ISC. See if it works properly first, and check the value against TPS. The service manual have all the procedures explained in detail. If you do not have one, get it. It is the best investment and you can learn alot.

1960 Sedan De Ville (sold)

1970 Coupe De Ville (sold)

1987 Mazda RX-7 (sold)

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Here we go with the varied opinions.

First question.

I assume it's a Northstar engine ?

If so, I think it's likely the ISC (Idle Speed Control) motor.

They tend to fail quite regularly, and they do act as you describe.

It's not too bad of a job to do yourself, however there are some setup things you need to do with the computer and plunger adjustment.

I hope you get some other opinions on this as well.


Looks like maremrak was faster on the post.

2008 STS V8
2016 Colorado Z71
1970 Corvette LT-1 Coupe

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