I drove to work today which takes about 15 minutes on the highway and when I got here and put my car into park the idle was surging from about 700 rpm to 1200 and back. Then it would go even lower and almost die. It has happened a couple of days in a row know. When I go out to start it again it runs fine. The problems seems to be happening more frequently know. Also it was doing it the other day when it was in drive which caused the car to want to surge forward. Where should I start. My car is a 87 mark lsc. I would really appreciate any help. Remeber I am still a newbie so please give it to me in newbie english. Thanks. :mad: :Bang :slam

Its a pretty normall thing. The ideling thing that is. There is a few things you can do to help it. So, its not as bad. I can't remember the links, though. . .

Check the PCV valve and screen. Clean and/or replace the IAC motor. Check vacuum lines for any cracks/leaks.

Check the PCV valve and screen. Clean and/or replace the IAC motor. Check vacuum lines for any cracks/leaks.

What is the IAC motor and where would I find it. Sorry for the dumb questions but I am still learning.

After checking for the previously mentioned mechanical items, get some SeaFoam treatment and run through the air induction system.

What is the IAC motor and where would I find it. Sorry for the dumb questions but I am still learning.

Have a look here:

http://www.lincolnsonline.com/article17.html

Have a look here:

http://www.lincolnsonline.com/article17.html

Thank you for the tips. I am going to get to work on it. Any idea how much a new motor costs. Also what is seafoam and were can I get it at.Thanks agian.

I forget, man. It's been a few years. Maybe $30 or so?

Does this only occur with the AC on? You may want to check for codes. This might pinpoint a dirty/malfunctioning EGR or other problem. You might also want to make sure that you're idle is set properly and the TPS voltage is ~.99mV.

Does this only occur with the AC on? You may want to check for codes. This might pinpoint a dirty/malfunctioning EGR or other problem. You might also want to make sure that you're idle is set properly and the TPS voltage is ~.99mV.

The ac was not on. What should the idle be set at. Also when I drove home it did not do it. It seems to usually only happen in the morning. I had the heater on would that make a diffrence. It is fall here it aint summer any more in Washington. Thanks for the help. Again what is seafoam?

600rpm

The ac was not on. What should the idle be set at. Also when I drove home it did not do it. It seems to usually only happen in the morning. I had the heater on would that make a diffrence. It is fall here it aint summer any more in Washington. Thanks for the help. Again what is seafoam?
The idle is slightly dependent on the engine you have, but between 700-800rpm is a good place for it. The heater might be putting an additional load on the engine enough to create the rough idle. It sounds like it might be EGR or IAC related. I think pulling codes might help clear this up.

Seafoam (http://www.seafoamsales.com/) is an engine additive that helps clean the engine of deposits. There are tons of places to add it to the engine, so you are probably best off doing a search to see many of the options.

Good luck!

SeaFoam is basically a carbon cleaner for the engine. Used as instructed, it does help a lot of surge problems caused by carbon deposits. It can be had at AutoZone, Advance Auto and other outlets.

On the 87 is the pcv valve on the top back of the block instead of on the valve cover, and were is the screen located. Also with the egr valve is it best to by ford ($145.00) or is one at napa auto ($99.00) alright. Do you just replace it or can you clean it. Thanks for the help so far. I am getting there. :yourock:

PCV valve info (http://markvii.homestead.com/pcv.html)

The EGR you can try to clean. If not, I don't think I'd trust anything other than a Ford part from the stories I've heard.

PCV valve info (http://markvii.homestead.com/pcv.html)

The EGR you can try to clean. If not, I don't think I'd trust anything other than a Ford part from the stories I've heard.

Thanks for giving me the web info. That is really helpfull.

Surge problems are common on these cars. specially if they haven't been tuned up.

PCV valve, PCV Screen, ICV Valve, EGR Valve, EGR Sensor, EVP Filter, and so on.
Map sensor could also be the problem too. but thats fairly uncommon for them to go out. oh and chekc the vac hoses too ESPECAILLY the one hose behind the upper intake near the PCV valve in the back.

yeah i probalby repaced myself from everyone else here....oh well.... :repost:

I cleaned the egr valve,iac,egr filter and replaced the pcv valve and screen and I think it is all fixed. The idle problem has not come back and I am getting better gas milege. I am going to go and get some seafoam and see what that does. Thanks for all the tips. They were very helpful. Once again you guys saved my butt and my mind. :yourock:

My car just started to do that in the past month ,but I haven't driven it in a while. You just helped me with the problem too.THANKS.

Check the PCV valve and screen. This is a usual suspect cause no one wants to deal with replacing the screen because its hard to access. I've heard from mechanics that this causes repeated problems with other things because the screen is constantly clogged, the other parts fail as a result of it.