cdougherty

Looking for a little help.

90 GT purrs like a kitten. Idle is smooth, response is quick. However, after running and getting on it a little, when I brake to stop and return to idle it wants to die and sometimes does. It's not all the time though. Sometimes I can drive it just fine and it doesn't seem to have an issue. At higher RPM and then down to idle seems to be the problem.... The check engine comes on, but that's fairly recent.

Things i'm going to do: Change Fuel Filter, new plugs/wires. After that, i'll be scratching my head. I did buy a coolant temp module cos I heard it also helps the computer regulate air/fuel flow and was thinking that might be it as well.

The stang II

try getting a new cap and rotor too.

tmoney302

I had the same problem with my 93 stang. Check you IAC or clean your throttle body, that might help. It worked for me....

cdougherty

Well I replaced the IAC (not going to buy parts from that Ford Dealer again, kind of pricey). I also put in the new plugs gapped at .054 and new 9mm FR wires. Fired her up and had the same problem, maybe a little better and it didn't die. So.... (I'm writing this for the benefit of others).

I did the following:

Removed the negative battery cable and let it sit for about 30 minutes to reset the computer. Then, removed the cable to the IAC and reconnected the neg cable and fired up the car. It quickly wanted to die because of the lack of air. So, I turned up the idle screw on the throttle bottle to get it to idle somewhere in the 2000rpm range. Once that was done, I backed off the idle screw to about 600-700rpm. Turned it off and reconnected the IAC cable. Apparently, this is to reset the base idle. It loped for awhile at 600-700rpm so I adjusted the top hex nut on the IAC plate. This plate I guess is optional, some people put it on and some don't. Fortunately, mine had it and I was able to pretty much eliminate the lope and have idle at 600-700. The needle still bounces a bit which I'd rather see sit steady, but not sure how to get it there.

I still need to:
Change out the fuel filter because I suspect that i've addressed the air flow issues, but not the fuel part.

Couple of questions:
I purchased a coolant temp sensor and haven't seen where that goes. I bought it cos I read that it affects airflow as well?
Also, when changing plugs, I removed some rubber hoses on the passenger side to get to them easier. What the heck do these go to? There's two good sized "valves" one on top of the other that they are attached to.

Anyway, I appreciate the suggestions from earlier.

PRO50SC

Instead of speculating, run the codes to see why the CEL is coming on.

ewgoetz

Do you have under drive pulleis on? Think those Hose's are for the air pump for the emisions stuff.

cdougherty

Ok fellas, back at it. I so far have done the following: Replaced fuel filter, plugs, new 9mm wires, MSD cap/rotor, new IAC. I know, I know... Here's the part where PRO50SC gets the glory.Dropped a couple of bucks on a new code reader and voila! EC 63 Throttle Position circuit fault, below minimum voltage.

Ok next steps: Get a voltmeter to test. Red wire - Green wire, Black wire - ground
Turn key "ON" but engine off. I should get a volt reading of .96-.99.
Based on the error code it says, "below" so i'm assuming that means the volts that the TPS is getting is going to be below .96?

So as I understand this can be adjutsted by loosening the two screws and "twisting" the TPS in one direction or another with the key on until I get at least the minimum reading? Easy enough if that's all correct.

However, I found an article on here that said TPS's can't be adjusted????? So, now i'm a little confused....

So does it sound like i've done my homework and i'm good to go?