[wildhorse]

Hi, new to this forum and having a problem with my 96 Mustang 3.8 V-6, replaced both head gaskets after one blew and ever since can't get it to idle or run right with the mass air plugged in. I'm currently getting codes P0171 and P0174 lean condition on both banks, fuel control system reached it's rich correction limit. It ran pretty good before I replaced the head gaskets until one blew. I've replace all 4 O2 sensors and the mass air. The compression is good and fuel pressure ok too. It seems like a bad vacuum leak, but I haven't been able to find one. Any Ideas?

[lemon]

if it wont idle, check the iac ( idle air control ) valve.

[99mustang232]

might be a leak at the intake manifold, after the head gasket blew did you drive on it much, how hot did it get?

[AtlanticBlue99]

How are the gaskets to your upper and lower intake? I had the upper intake manifold gasket leak in my car and the idle would fluctuate from 700-1100 rpm and back and the power was no longer there at all. The car progressively got worse and became undriveable until I got a new gasket put in.

I also threw a code for "high intake temperature" or something along those lines.

[wildhorse]

I didn't drive it much after I replaced the head gaskets, and it didn't overheat again. Voltage going to the IAC is normal at 12.10, I pulled it and replaced the gasket, the valve didn't look dirty. What other kinds of checks can I make to the IAC? I also replaced the gasket between the upper and lower intake manifolds a second time, suspecting a vacuum leak there. I also pulled the valve covers to make sure all valves were operating like they shoud, thinking a pushrod might have been off because some of them are a little hard to see when putting them back in. Yesterday I cleared the codes, drove it again and scanned it with the Auto X-ray and got both the lean codes again plus a P0113 code:"Intake air temp curcuit high input." While I was scanning it I also had a fuel pressure gauge and vacuum gage on it. The fuel pressure seems ok at 35lbs at 740 rpms, 32lbs at 1,000 and 32 lbs at 2,000. The vacuum was only 10 inches at the lower rpm of 740, 15 inches at 1,000 and 18 at 2,000. That is down from the 16 to 20 they recommend at idle, but the idle is jumping up and down soooo bad, I'm not sure if the vacuum reading is really telling me much. I've probed around with a heater hose at my ear and can't hear any leaks. The really wierd thing about all this is when you unplug the mass air the engine settles down and idles and runs pretty good, not perfect, but much better. This is really getting to me and my wallet too. I appreciate all your input and will accept any suggestions. Thanks, Wildhorse

[99mustang232]

maybe the IAT sensor?

[AtlanticBlue99]

Either that or check the seals on the upper and lower intake manifolds again. I threw the P0113 code when my gasket leaked; maybe your manifold is cracked/leaking itself?

[99mustang232]

if you do pull the intakes again be sure to check the mating surfaces to make sure they are truely flat, if your car was to barf via head gasket and the temp was to get very high it is possible to warp, thus creating a surface that is unsealable via gasket.

also be sure to check the 3/8" hose that should be installed just behind the throttle body and faces the fire wall. it is under the bottom of the upper intake and is invisible when the upper intake is installed.

[big-t]

These guys know what theyre talkin about, do as they say and if you still cant figure it out call someone like napa theyre pretty smart about these kind of things.

[6stang]

Hey, this seems like as good of a place as any... I have a problem, I just replaced head gaskets (as well as most others) in my '97 3.8L Mustang with Fel-Pro gaskets ($237 for the complete set!). While it was apart I also changed the belt tensioner and idler pulley. And the spark plugs and wires (Autolite platenum plugs and after-market wires). Now the car is all back together and has stopped belching thick white smoke from the tailpipe (after 20+ minutes of driving). Now The check engine light is on and it runs and idles rough and lacks power. The check engine light was on before we took it apart (probably from the head gasket) and ran well before the head gasket went. Before I took it apart I gave that Prestone Blue Devil stop leak a shot. Coolant was pouring out of the exhaust like a faucet; so badly we needed a drain bucket. Needless to say, it didn't work. So there is my situation, any advise regarding anything mentioned would be greatly appreciated.

Thanks in advance,
-Nathan, MA

[Onemanzu]

kk few things...

You changed your fluids right? just checking...

second disconnect your battery for 15 minutes and let it reset the computer... after that drive around the block to see if you get codes again... then take it to autozone and have them read if you do get some...

if they don't come back ... job well done... if they do come back here and ask about it

for those of you who won't notice this is an old thread brought back... don't call out someone else prior to stang3.8's post

[6stang]

Yes, I did change the fluids. 4 Qts heavy weight motor oil + 1 Qt Diesel fuel= engine internal detergent! Ran it with that for about 15 minutes, drained it out and changed the filter (used Fleetguard LF3339) and poured in Castrol GTX 10W 30 High Mileage formula. I also filled up with water and will flush once running properly then drain and refill with 50/50.
Update: There was a code for misfire in cylinder 3. We swapped out the injector with the one from cylinder 1. Dumped 2 bottles of Xcel injector cleaner into the tank, drove it, and it actually seemed better. Runs great when you really get on it. Once you slow it down and try to let it idle is starts to run shaky again and the check engine light comes on for a misfire in cylinder 1 and 3 code. Hmmm... what do you think?

Thanks for your help,
Nathan, MA

P.S. I am really beginning to miss driving my 'stang!

[Onemanzu]

i think you might want to check your spark plugs... swap them out for some new copper ones for now

[ROUSHME661]

yeah if its calling for misfire it might be ur spark plugs sometimes when ur trying to put them in they crack a bit and with a bit of time they will crack even more u might not even notice it till it gets real bad also check if the wires are connected properly

[6stang]

Latest: My brother decided to try a diagnostic experiment. The car had thrown a code for misfire in cylinder #3. So he decided to swap fuel injectors with #3 and #1 cylinder. We got the car all back together and began to road test the car and within a short time it threw a new code. Sure enough misfire detected cylinder #1! I decided to take the cheap way out: "One injector, please." "Alright, that will be $66.06 please." I wish I could afford all six but that is simply outrageous. Ford, I love that Mustang but I sure do f-ing hate you! What do you think?

Thanks,
Nathan, MA

p.s. My automatic gear selector is really hard to move these days. What can I do to free it up? I would like to lubricate it; but how would I do that?

[tims3.8stang]

pull your egr off and clean the piss outta it and check it for internal leaks witha vacume pump and blow on the inlet side it you can hear air leaking through it it neeeds replace i just did that with mine tonight and just by cleaning it the car runs alot better and smoother but it still will need replaced if its leaking vacume because it causes both banks to run lean and then thhe pam trys to compensite for it and when it cant get enuf fuel into the motor it will stall and run rough to the point of not being able to drive it

[Onemanzu]

you should have looked for a set of a GT mustang... used of course but they are always available ... never fails i know people who have found cobra ones for like 80 for 8

[6stang]

The motor is dead. I think it threw a rod. The pan is now cracked and there's a -BANG-BANG-BANG- when the engine is running. After we replaced the one injector I drove it for like 2 weeks before it went. It was still a little bit shakey at an idle, but seemed like it drove fine. I wonder what went wrong. Any advice on doing a motor in a '97 V6 Mustang? Also, I saw an '86 2.3L Mustang LX in the local Want Ad for only $850. That seems like it would be good for transportation to and from work while my brother and I do an engine in the '97. I don't know much about them though. Are they any good? Advice?

[Hourofpain]

personally it could have been a couple things.

a timing issue,
a deteriorated lifter.
but i think your injector pumped too much fuel in the cylinder.

if you can get the top end off.
Pics would most certainly help.

[Onemanzu]

i say its time to overhaul your engine... which sucks but might be the best way to solve your problem...

oh and 2.3s will keep going until the world ends... we have some extremely biased 4 bangers on here ... you should ask them for more info