New Pony Owner Just Bought 94 Gt Convertible High Idle Issue Help

[ChicoNJ94GT]

Thanks first off to all you guys who take the time to read these and reply.

Moving on, I just bought my first mustang. It's a 1994 GT Convertible Auto. I just ordered and got in Moog Racing Wheel Bearings and assembly, B&M Shift Kit, Cardone Select Mass Air Flow Sensor, and it already has a MSD Igniton, full exhaust minus headers. Also just ordered new convertible top, changing from stock tan to black.

Now the issue at hand, I was enticed to step down on the gas when I was almost clipped by an apparent drunk driver. In an attempt to separate myself from him something happened after the down kick. When I exited the highway and approached a stoplight my engine wouldn't come down below 1,000-1,500 RPM. It was almost enough so that if I left in drive and had toe on brake it would drive through them. So I popped into neutral at each preceeding light until i got home. Now the young fella, lol im only 33 but the kod who owned b4 was 19 and a good friend, told me it was the mass air flow sensor, so instantly bought a new one overnighted it and BAM after installing same freaking issue. High Idle. Now another note to this diagnosis when I first pulled over to see why engine was idling high I first looked at the accelerator cable and saw right next to it was a grey cable connector and after sending good Mechanic friend pic he said it was cruise control cable. That was FREELY hanging unconnected to the small Metal joint Attached to throttle. I reattached hoping that would help but that did nothing. The accelerator cable it intact. Any suggestions as to what I should check and in what order to eliminate the frivolous spending such as the new mass air flow sensor that didn't fix anything. I do know However a 23 year old Mass Air Flow probably wasn't a bad fix anyway, but as it wasn't the cause and effect of the current issue I could have spent that 200.00 more wisely.

So again, any ideas and suggestions are welcome. I've wanted to own a mustang since I was a little boy. This one is in fair condition, needs TLC for sure, but for the price I got a great little project car to start developing my tuning skills. I won't lie, I never tuned American, I used to tune my Jap traps but am done with the little boy cars. I love the shake and rumble my baby puts through me daily and am missing driv8ng her already. Thanks for the help.

-Chico

 

[General karthief]

In the 5.0 tech/how to threads there is a surging idle checklist, I know you don't have a 'surging' idle but go through the checklist and it resolves problems like this, it will also show you how to'run the codes' if it does not (but I think it does) there is also a thread that shows how in the same tech threads. As always make sure your 'tuned up', good plugs, wires etc and connections for power and grounds are good and clean, as you should know from working on those 'little boy' cars, grounds are very important to the efi system.
Thanks to jrichker and others that put the tech/how to section together, they have made me sound smarter than I really am.

 

[jozsefsz]

Since this all happened after a wide-open-throttle event, you might try disconnecting the throttle cable to see if it's holding the throttle body open. A 20+ year old cable might be frayed or otherwise binding. The throttle body might also be sticking, I'd try cleaning it up and seeing if everything moves freely.

I agree with karthief, checking your base idle settings using the checklist will help fully diagnose the system.

 

[apothicca]

if you have the money, get the top installed professionally.

 

[Bad69cat]

Yeah - could be as simple as the throttle linkage is not operating the full length for whatever reason - pull off the air intake and look in at the throttle blade and see that is closes fully when you operate the pedal/cable. Give a a quick cleaning while your there to be sure it's not sticky. you should be able to feel or see any issues. If it's really filthy you may need a full blown take it apart and clean it good. Check the condition of all your vac lines as well - do they feel soft or spongy? make sure no loose bolts or places for it to suck extra air......etc. Basic stuff goes a long way to keep little gremlins from popping up...