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My 1988 Ford Mustang 5.0 recently has started bogging when I start up the car. The idle goes up and down and will die unless I keep giving it gas. This is happening before I even put the car in drive. Once in drive it will idle up and down and almost die until I drive it around for maybe 5 -10 minutes.. then its fine, no problems at all. This happens when the car is sitting at a light or sitting in park. If I drive the car around.. park for like 10 minutes or so, then start it up again and drive, it seems fine. It seems to happen only if the car is sitting for a few hours or so. After I drive it for a few minutes after starting it is fine. Even at stops it idles perfectly. Just happens when I first start the car after awhile.
I hope any of this made sense and someone can give me thier input!
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That's funny, my cousin has the same problem with his car. The car will go between 400 and 1000 RPM's, like the comps trying to find the right idle, and eventually will get less and less until it finds it. Seriously, I think the only thing we haven't done yet is check the TPS voltage, though that will be next. For you, I'd do the same, plus make sure al hoses are connected, vaccuum lines, everything. Also, check your grounds. We had forgotten to reconnect a ground to the firewall after we swapped his heads, and it was doing it really bad. We connected the ground and it got a lot better.
EDIT: Also check the O2's, it seems as though your car does it in a closed loop, i.e. when the car's warming up. If you have an aftermarket temp gauge, check to see what temp the idle stops surging. Maybe Lloyd can comment on what he thinks it is. Something else that affects the idle in a closed loop.
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I've gotten lots of differnet suggestions when I call around and describe my problem. Temperature sensor? Idle Control Valve? I can change my own oil but that's about it.. I'll probly have to take it to a diagnostics place. I dont have an aftermarket temp guage.
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I forgot to mention.. the odd thing was is this didnt start happening until the morning after I took off my battery cable to change my brake light switch... it was probly disconnected for a half hour. Do you think I messed up the computer chip or something?
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For the IAC, which is the little cylinder looking thing attached to the throttle body, take it off, take it apart, and spray some carb/brake/throttle body cleaner in it, let it dry, and then reinstall it. See if that helps at all. I don't *think* it would be the temperature sensor (if what they're talking about is the ACT on the lower intake), I've had mine off and my car idled fine. Might as well try what you can before you send the car to a shop. Might end up fixing it, and how pissed are you gonna be when you have to pay $50-$100 to find out it was something you could have done at home in like 5 minutes?
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I know you're right but I get nervous when I work on my car by myself. I dont know if I want to take apart any throttle body pieces.. for fear of not being able to put them back on or something. I used to change the oil and replace minor parts but anything else I just feel more comfortable taking it somewhere. I was just seeing if I could eliminate some possibilities before I bring it in. I appreciate you taking the time to reply.
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Quote: Originally posted by Sicy Stang on 01 April 2003 I forgot to mention.. the odd thing was is this didnt start happening until the morning after I took off my battery cable to change my brake light switch... it was probly disconnected for a half hour. Do you think I messed up the computer chip or something?
Didn't see this the first time. Try disconnecting the battery again and letting it sit for about 30 mins. This resets the computer. If this doesn't work, and you're not comfortable working on the car, I guess it's time for the shop.
How about this. Call some auto parts stores, see if they have a code scanner to loan you (I know Autozone loans out tools, I'm not sure about a code scanner) Pull the codes, see what it tells you, then post the codes on here. We/I will check them out and see if we can't figure it out from what the computer is telling us is wrong.
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Man i had the samething wronmg with my 86 stang soon as i started it it would idle up and down from like 400-1000 rpm and in first gear at a light it would all of a sudden do it. i found out that what was wrong with mine was my map sensor went bad on it and my computer chip i had to replace also, so try those and see if it fixes it.
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Quote: Originally posted by 91GT5.0 on 01 April 2003 Try disconnecting the battery again and letting it sit for about 30 mins.
Ok.. I'm doing that now.
I already told my boss that I was going to be late tomorrow because I wanted to drop off the car.. so if this doesnt work I'm just going to take it in. They said if they do the diagnostics and end up fixing the problem they'll take half off the diagnostics so that's cool.
I think I'm going to buy that code reader thing.. I heard they're not very expensive and it could save me money in the future. I remember something happening years ago that made me want to get one.. I should have got one then.
You guys are very mustang knowledgeable.. I like this board
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Might want to clean out the Mass air with some electronics cleaner. Put some on a Q-tip and GENTLY swap the wire elements. I know one guy who bought a 95 Cobra the was dogsh*t slow (I know cuz I test drove it before he bought it, took it to JBA, they cleaned that out, he gained 70 hp on the dyno!!
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Ok my car is at the shop. They just called me. It was indeed the Idle control valve that went bad and apparently was covered in carbon So........ they're going to change that and also do a complete cleaning of the throttle body, and something about the fuel rail something or other.. in any case everything will be de carbonized and they said my car should run stronger and have more power.
Its going to cost a lot but I couldnt have done it myself.
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Joined: 4/1/2003 From: United States Status: offline
Oooo throw me back! I like the sound of that.
Thank you for your input.. I'm sure for a very knowledgeable car enthusiest its easy, but for a 110lb girl that pretty much only knows how to change the oil, I feel better paying someone else to do it.
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Joined: 3/7/2003 From: United States Status: offline
Quote: Originally posted by Sicy Stang on 02 April 2003 Oooo throw me back! I like the sound of that.
Oh, you're one of those kind of girls. Nice. . .
No problem, that's what we're here for. To ask questions and to help each other out. Glad your problem wasn't that complicated. After 4 months we haven't figured what's wrong with my cousin's car. It's kinda sad actually. . .
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Joined: 4/1/2003 From: United States Status: offline
Argh.. 2 more hours of work until I can go pick up my baby!
I dont suppose you have taken your cousin's car to a mechanic? I know most people here work on their cars themselves, but sh*t after 4 months I'd be so frustrated I would pay any amount of money to fix it!
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Joined: 3/7/2003 From: United States Status: offline
Well that's the thing. It only surges on start up, for like 5 seconds, then it's fine. And the car runs hard as f*ck, so it's like if it's not broke why fix it?. . . sorta. He keeps up with a 306 w/ Powerheads, RPM Intake, F-cam, 24 lbs-ers, 75mm MAF, 65mm TB, Full exhaust, and 3.73's. All he has is P&P stock heads, Explorer intake, and full exhaust. That's it. Even has the stock 2.73's. (Keeps up with means less than a car length) Sh*t, he beats cars with the same mods with 3.73's on the street, which is unheard of with stock gears. The car is a freak.
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Idle problem - help? - 
I'll probly have to take it to a diagnostics place. I dont have an aftermarket temp guage.
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