Engine dies when shifting from park to rev or drive

[Casey6463]

Had minor engine work done to my 95.New heads, cam, intake. After having the work preformed I took the car to have it chipped. Now when I shift from park to either rev or drive, the engine dies. if I give it gas, it will stay running. And to make it even stranger, sometimes it will shift perfectly. I changed the sensor and the problem persists. The engine builder says its the chip, the tuner says its the right on the money but... Any ideas.

 

[toyman]

Had minor engine work done to my 95.New heads, cam, intake. After having the work preformed I took the car to have it chipped. Now when I shift from park to either rev or drive, the engine dies. if I give it gas, it will stay running. And to make it even stranger, sometimes it will shift perfectly. I changed the sensor and the problem persists. The engine builder says its the chip, the tuner says its the right on the money but... Any ideas.

What sensor did you change? The problem may be the IAC valve. The purpose of the IAC is to increase/decrease air flow at idle to compensate engine load changes ie. shifting into/out of gear, A/C cycling on/off, etc.

 

[Casey6463]

Thanks for getting back to me. I changed the IAC valve (sensor) and the problem still persisted. Wondering if the new valve is no good. I openned up the bleeder screw on top of the TB and that didn't work either. Any other areas I should check.

 

[toyman]

With respect to the air bleed screw close it (gently) and back it off about 1 1/2 turns. Any adjustment from there is very small.

 

[Casey6463]

thanks, will do

 

[BlueSaph95GT]

I had/continue to have the same issue with mine. I changed the TPS and IAC sensors and put a PA performance high output alternator on (to offset the underdrive pulleys a bit) and the issue is better, but still not gone. My MAF is new, so I know that it's not dirty, but you might want to clean yours if it's stock/old as that can help too. unfortunately, this seems to be a problem with the SN95 5.0's; i have a great SCT tune from the guys at Sutton Ford (Factory Stock and Renegade racers/Ford dealership), so I know that's not the issue. the only thing I can tell you is that it helps to warm up your car. if I let mine run and get up to operating temps before cruising out of the garage, the problem is much less likely to happen - at least in my experience. the only other thing I can think of that seems to help is to kick up the idle set screw a little bit, but it still won't solve the issue completely. good luck and I hope this helps out.

 

[stangbangerrick]

Had minor engine work done to my 95.New heads, cam, intake. After having the work preformed I took the car to have it chipped. Now when I shift from park to either rev or drive, the engine dies. if I give it gas, it will stay running. And to make it even stranger, sometimes it will shift perfectly. I changed the sensor and the problem persists. The engine builder says its the chip, the tuner says its the right on the money but... Any ideas.

I built a 331 stroker for my 95 stang and had it dyno tune witha SCT chip. It ran fine for about 2 months ( its has a manual T5) Then it started to stall when I would take my foot off the gas to shift form a stand still into first. My tuner said there was nothing wrong with the tune and that I needed to look else where. Hooked up a LMI to check A/F ratios and found that the ECM would not go into open loop. I finally located a used ECM from a 94 gt and put that in and took it back to my tuner and he told me that the bosch O2 sensor were bad (1,600 Miles) so I gave him the orginal ford (105.000 miles) O2 sensor and the car ran great once the heaters in the O2 sensor warmed up (using long tube hedders). Iwent back and bought some factory O2 sensors and car runs great. Because of the long tube hedders I still let the engine warm up a little before I engage 1st gear.

 

[BlueSaph95GT]

for reference, i am running the stock ford oxygen sensors too

 

[stangbangerrick]

for reference, i am running the stock ford oxygen sensors too

I would check the IAC unit on the throttle body. Does the a/c work? Have the car in park and turn on the a/c, there should be an increase in the idle speed and the radiator electric fan should come on. Since your mustang has a automatic transmission the ecm has two settings for engine rmp one for the trans in park and one that would increase fuel/air when you take the shift lever from park to drive/reverse these fuel and air tables should be adjusted when your tuner did the SCT chip based on your mods your A/F ratio reading when he was tuning your car on the chassis dyno. Unless this is a mail order tune? If its is you need to have the SCT chip tune when it is in your ecm when the car is on a chassis dyno.

 

[2002BLGT]

I built a 331 stroker for my 95 stang and had it dyno tune witha SCT chip. It ran fine for about 2 months ( its has a manual T5) Then it started to stall when I would take my foot off the gas to shift form a stand still into first. My tuner said there was nothing wrong with the tune and that I needed to look else where. Hooked up a LMI to check A/F ratios and found that the ECM would not go into open loop. I finally located a used ECM from a 94 gt and put that in and took it back to my tuner and he told me that the bosch O2 sensor were bad (1,600 Miles) so I gave him the orginal ford (105.000 miles) O2 sensor and the car ran great once the heaters in the O2 sensor warmed up (using long tube hedders). Iwent back and bought some factory O2 sensors and car runs great. Because of the long tube hedders I still let the engine warm up a little before I engage 1st gear.

That is a tune issue , HEGO delay was probably not changed in the tune to let the car know you are running longtube headers