96 GT stalling and rough idle when hot

D96V8Stang

New Member
Joined
Sep 5, 2017
Messages
13
Reaction score
0
Alright, before anyone says it, I have looked at other forums saying this issue could be the IAC, which I do plan to replace, after some input from you guys. My car has a heating issue so I thought it was vapor locking or something, but the fuel rails have pressure in them, and there's not a vacuum in the tank, both of which others have told me would be indication of vapor lock. Basically, I live in West Virginia, and I drove my car to a city in Ohio, about 150 miles away, and the car did fine...well as good as my car can.(I've wrecked it and pulled the condenser off for air flow to the radiator, which had been replaced because it was bent, all is good now though, sort of) After I got to where I was going in Ohio, the car started to have a rough idle in the neighborhood where I was staying at a low speed and low RPM. Then the next day I went to visit another friend that lives about 50 away from where I was staying. Getting there was fine, no issues. When I left after letting the car cool for 3 hours, I took off again, accidently left my a.c. on, which left the fan on, and the car heated up and stalled, but it didn't go above 210 the whole time. I plan on getting an egr block off plate and the new IAC valve, but is there anything else I should look into? Also think i need to replace the ccrm because my fan doesn't come on at the right temps(I think) and I've already replaced the manifold, temperature sensor and switch, and I have no other ideas.
 

white95

Apex Junky
Admin
Joined
Dec 30, 2007
Messages
20,539
Reaction score
8,574
Location
Prairieville, LA
Taking a stab in the dark here but have you tried flush out and then "burp" any trapped air in the coolant system?
 

BigBore96

Active Member
Joined
Oct 2, 2012
Messages
882
Reaction score
172
How old are the coil packs? Id check into them as failing packs show theyre failing when warm but can work fine when cold.

Also regarding the IAC. Clean it before you replace it.

Regarding High temps. Drill 3 holes in your thermostat (3/16 IIRC) and reburp the system.

Dont throw money at a problem guessing. Its what bad shops do. Figure the problem out the first time and do it right while you save unnecessary money.
 
OP
OP
D

D96V8Stang

New Member
Joined
Sep 5, 2017
Messages
13
Reaction score
0
Taking a stab in the dark here but have you tried flush out and then "burp" any trapped air in the coolant system?

I have burped the system, and I flushed it a total of about 10 times when I replaced the rad. Replaced the intake as well because it was leaking.
 
OP
OP
D

D96V8Stang

New Member
Joined
Sep 5, 2017
Messages
13
Reaction score
0
How old are the coil packs? Id check into them as failing packs show theyre failing when warm but can work fine when cold.

Also regarding the IAC. Clean it before you replace it.

Regarding High temps. Drill 3 holes in your thermostat (3/16 IIRC) and reburp the system.

Dont throw money at a problem guessing. Its what bad shops do. Figure the problem out the first time and do it right while you save unnecessary money.

I've already purchased the IAC because I had a gift card to buy it so it wasn't any money out of my pocket. The coil packs are probably the stock ones on the car but I don't honestly know, I'll try to find any indication of them being replaced when I get home this evening. I'll also try the holes in the stat and see if that helps with the cooling issue. I noticed last night when I had the car hooked up to a computer my uncle let me borrow, the fan would kick on around 210, on low, and wouldn't go into high l even with the A.C. on, is that right?

I forgot to mention in the original post, the car has three codes that it's had since I bought it last November, P1443, P0420, and P0430, any of those have any effect on the issue at hand?
 

BigBore96

Active Member
Joined
Oct 2, 2012
Messages
882
Reaction score
172
The first code is for your evap system while the other two are rear o2 related. Im assuming you have an offroad mid pipe with no mil elims so the o2 codes are due to that if I am assuming correct.

The evap code is common especially on an old car. The lines are likely rotted/pinched.


Does the fan ever kick onto high speed? You can easily ground the fan to always be on high when the key is on.
 
OP
OP
D

D96V8Stang

New Member
Joined
Sep 5, 2017
Messages
13
Reaction score
0
The first code is for your evap system while the other two are rear o2 related. Im assuming you have an offroad mid pipe with no mil elims so the o2 codes are due to that if I am assuming correct.

The evap code is common especially on an old car. The lines are likely rotted/pinched.


Does the fan ever kick onto high speed? You can easily ground the fan to always be on high when the key is on.

The fan will kick in to high if I unplug the sensor for it in the intake while the car is running, that's the only time I've had it go into high. I've replaced the temp sensor and the temp switch in it numerous times thinking it was causing an issue, but I put a mechanical gauge in line and it shows a steady reading that is comparable to that of what the computer gets
 

Latest posts

Forum statistics

Threads
77,435
Messages
1,502,106
Members
14,917
Latest member
virocanah

Members online

Top