IAC cleaned and intake below cleaned out, tb cleaned out some, checked all intake bolts, pcv valve is good and tight, no other weird vacuum line conditions, air intake disassembled, reassembled. Vacuumed lines replaced from the purge box (Behind pass. fender), wiring moved from under air filter box, maf turned a bit to match air filter cone box,

BTW THE check engine light was on prior to all of the work today on easter.....


What else to check on why the idle stil is hanging?

I drove it and the idle does drop fast (1st start up though since battery was connected-- may not do it again though)--- idle did "surge" some when it droped fast---

base idle at a stop is 1000-1100. i am pretty sure the idle should be around like 80-90? right?

The idle will stil hang around 13-1500 at times. I only went for a short drive. A few WOT in second gear and third.

SO what gives? I have searched here, svt performance, mustang evo, corral, etc.

COULD IT BE the TPS?? I'l get a volt meter tomorro while getting interviewed at auto zone and advance hehe.

Let me know if anyone knows. Noticed my threads have quite a few views, though no help.......thanks

 

Does the car still have IMRC's? If so, have you checked to see if they are operating correctly? They may need cleaned.

 

l has them. How would i go about cleaning em?

How would that cause a CEL code P1506 still? I keep saying the same code. WTF. Even after i unplug the battery, wait, hook back up, start and run, the CEL same code and all symptoms come back within about 5 minutes, a few shifts, stops and take off's.

 

I missed what code you had. If the IAC is good then it is a vaccum leak of some kind.

Does it get worse after the car has warmed up? If it does that should tell you that something is expanding as it gets warm and then leaking.

 

The idle hangs for a longer period when the car is warm. As in-- a trip on the highway for 55 mph or higher for 10 minutes or more.

I have sprayed starting fluid and any kind of super flammable spray trying to find the leak.

I did replace the vacuum line from the charcoal canister to the cylinder loking piece, into the next black hanging piece and the line into the intake, at the bottom of the TB.

I know, the description of the pieces arent really alot of help, but in short, its the piece from the canister to the bottom nipple (hehe) below the throttle body.

In the mornings when cold, the idle will drop back down within about 10 secs. Now, i have noticed that if i shut the car off and restart (as in turn the key off and back on) the idle will come down and "relax" for a bit --- around 1100 rpm.

Let me tell you, this is getting really annoying. Mileage has dropped way the f- off. Just about a quarter tank of gas used to go around 25 miles.....

 

Well a decrease in milage can be caused from a vac leak as well. Have you check the trq on stuff?

Like intake, t/b, etc.......

 

yes i have. Size 8mm (5/16) checked all the bolts on the lower intake, the lid, the tb, all hoses leading to the tb. Air intake is the stock piece still has air silencer on it as i didnt feel like removing it yet.

Clamps are tight enough. Air intake tube is correctly seated to the TB along with it correctly seated to the MAF. The intake air temp sensor has been cleaned off, along with the maf three times now. Nothing is missing or broken.

Though I did notice the upper intake lid has been previously repaired. The "tongues" where the bolts go through on the lid have been welded back on in two spots. I sprayed some starting fluid on those spots specifically and no rise in rpm.

 

Now could it be that some one jacked with the throttle screw due to the iac being faulty at one point?

When I first noticed the weird idle, i pulled the IAC oiff and found out the gasket had no holes. I poked holes in it and it was still the same so i replaced the iac.

the condition only got worse when i pulled the tips off the mufflers.

Put the tips back on, shitty stuttering. SO I changed the plugs.
Now the condition of the shitty idle is still there.

 

OK so i went out to the car---
Throttle body adjustment screw is turned all the way down...

JUst for shits, I un pluged the iac. Went for a drive and holy hell, it boils the tires all the way through first. no dumping the clutch just lay into the gas.

So, if it still ran fine with the IAC unplugged, what the hell does that mean?
Prevously, the iac had no holes in the gasket and i now have one with holes. WHy wouldnt there be holes in the previous one?

The iac, again, is new. If it doesnt need the iac to run correctly but still has an engine light-- does that mean there is a serious vacuum leak??

 

Anyone have a vacuum diagram for the 96-98 cobras?? hmmm.

 

as the previous stats, i unplugged the iac

Well now I have it plugged in, though the gasket has no holes in it now.
Replaced it with a homemade one.

I started it today, let it run and listened and i mean I listened to it really f-ing close.

The rear of the upper intake (the lid part) right at the back where it meets the lower intake seems to have an odd cold spot. A cold spot as in where air feels like it is blowing by. Could that be a vacuum leak?

I have to wait until I get paid to get a gasket--- but could that be it? ANy previous fixes for anyone with this problem?

Still have code p1506

 

Quote:
Originally Posted by HandsomeRob
Yea I just pulled off the upper to replace injectors
I put a new gasket too

Take the upper intake off and make sure it's set properly on the gasket. Also tighten the bolts in a cross hatch pattern, make sure all vac hoses are connected with a good seal. If you disconnect the iac and the idle stays the same that means the motor is sucking air from another source ie; intake leak,vac leak

I would definatly not drive the car!! with a leak like that your probably pushing some extremely lean conditions

Did you have an idle problem prior to intake removal




FOUND ON SVTPERFORMANCE>>>> SO it could be the intake lid then? as I feel what feels to be air moving past my hand on the back/ rear