I cant get my car to idle

[MurdockSVT]

ok so i have been dealing with this problem for about 2 months now. It originally started when I replaced all the gaskets on the engine upper and lower intake valve cover throttle body EGR and IAC. When i put it back together it didnt want to run, at all. I thought simple vaccum leak so i checked all of the hoses on the manifold, they were all tight and in place. so then im thinking well maybe i have a leak in one of the gaskets so i take the ole butane torch out and start feeding butane into the seals to see if i could get the idle to surge, no luck still just rough as all can be. So now im thinking its the IAC. Well put a new one of those on from autozone, didnt change a thing. So next im thinking MAF, took that apart and then cleaned the filaments with an electro solvent, added a CAI with a conical K&N put it back together and still it wont idle. on top of all of that, the car doesnt want to drop RPMs like it should when i let off the gas.

here is exactly what it is doing so please anyone give me ideas....

when i first start the car up, I have to play with the gas or it will die, this takes a few minutes before i can even get the car staying running. After that point the idle will surge from 200-1600rpms and just keep doing it. Once i get about 5 miles on it and it gets a little heat into it, it then idles at about 500 but its really rough. The throttle response doesnt seem to be the same and the rpms are not very snappy at all, at least not from what it used to be.

My next theory is that somehow i have a bad vaccum to the fuel pressure reg and that its getting too much fuel on startup and part throttle. anyone please

 

[deftsound]

go get a code reader and test to see if it throws any codes, i h ad the same problem for a while, make sure all the bolts to the manifold are torqued down to specification, also make sure your egr valve and pcv valve are operating right

 

[mackey]

My guess is it is a MAF problem. I had that same exact problem. You should find a buddy with another maf and just try it out. Trace your wires back a little, there should be a connecter, move that around alittle. Mine is coming very loose and has crappy connections.

 

[ram360]

Sounds like a vacuum leak to me.. I would make sure you connected everything back up again.

 

[wyominghotwheel]

vacuum leak.......take a can of ether and check for leaks......(starting fluid).....but you definetlly have a leak..........hotwheels

 

[D347643]

when you replaced the lower intake to head gaskets did you cut out the port for the egr? my car did the same thing after my cam swap and i took my engine apart and found the problem. also make sure your lower it torqued. if you have a lot of buddies that smoked have them blow smoke through a vac line and also check how much vac you are pullin at idle.

good luck

Drew

 

[92GreenGT]

My car does the same exact thing. I'm going to pull codes and see what it says. I have a 75mm MAF, that im going to put on it and see if that changed anything. Just take it one step at a time till I have it fixed.

Does anyone know a site that tells you how to pull codes with a paperclip? I have heard of people doing this, but dont really know what exactly to do. Thanks

 

[92GreenGT]

My car does the same exact thing. I'm going to pull codes and see what it says. I have a 75mm MAF, that im going to put on it and see if that changed anything. Just take it one step at a time till I have it fixed.

Does anyone know a site that tells you how to pull codes with a paperclip? I have heard of people doing this, but dont really know what exactly to do. Thanks

 

[HISSIN50]

as i recall, some of the AZ IAC's are supposed to be installed upside down - is yours?

pulling codes helps a good deal. pay attention to ECT, ACT and (aforementioned) EGR codes.

a stockish motor will pull 15-20 inches of vac at idle.

here is a link to JRichker's code pulling with a paper clip.

http://forums.stangnet.com/showpost.php?p=4631870&postcount=9

good luck.

 

[92GreenGT]

The car has about 16-17 inches of vac at idle. Thing is, I can rev it up to about 3 grand when it comes back down, its like the car doesnt catch an idle and it will go down to 350-500rpm and almost die out, but will finally pick back up. The IAC valve can only be installed one way, unless I didnt pay that much attention to it.

Car has real bad throttle response too, but im sure thats from the TPS sensor needing to be set. Got to get a battery for my voltmeter and I will set that.

 

[DMAN302]

Warm it up and adjust the idle screw to where you get about 900rpm constant (where surging stops), then shut off engine and turn key to on position. Check TPS voltage for .85-9.5v, then uplug battery and leave for 10 minutes. When you restart you may find it finds a nice idle somewhere about 900-1000 if not try again, also the computer will fight you for a while but often comes to accept the idle and not hang and surge. After my H/C/I install the car would surge and hang, I found I could no longer hold my 800 idle without it being VERY quirky and had to settle for 950 after playing with it as above about 5-6times.