wep0520

I know this is a mustang forum but engine and controls should be the same i hope. I recently purchased a 93 tbird. After the car warms up it idles fine. When the car is cold it acts like it has a choke, i have to rev it a couple times for it to keep running and then it idles rough. After the car warms up it idles fine. Normal driving it has a hesitation bad enough where i have to feather the gas pedal, it cruises fine on the highway after u get it up to speeds but if i give it too much gas it will act like is choking out, or starving. I tried running it with out the air cleaner but that made no difference at all. I pulled the codes and i got lean o2 sensors and poor egr flow (egr is currently blocked off but that made no difference) there are no stored codes, just the running codes. Does anyone have any ideas. I have already replaced the feul filter and feul pressure reg and they gave the car more power but didnt fix the problem.
5.0 HO automatic.

keith28fykerd

may be a bad thermo-temp sensor it tells the computer if the engine is cold or operating temp, it tells computer to add more fuel to engine when its cold ,and increse idle speed,thats why efi dosent need a choke, and redirects comuter when engine gets warm, these engines use two of these sensors , one controlls the h-c gauge on the dash, the other tells the computer how hot the engine is, they ore located on the front of the intake manifold threaded into a coolant passage

1ATony

Also check the catalytic convertor, and the pug wires,cap and rotor.

Grant218

I know how to fix the problem you have. it happened to me on my old mercury cougar XR-7. 1. it may need a new MAF sensor, mass air flow. 2. go to autozone and buy a can of seafoam. its pure petrol. pour 1/3 of the can in your oil, 1/3 of the can in your gas tank, 1/3 of the can in the brake booster or pcv valve. after doing the seafoam treatment your cars rough idle should go away and throotle response should be better too. like i said if it isn't the MAF sensor just buy a can of seafoam.

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"horse power gets you there, torque keeps you there"

geesey255

quick question, i have a 95 150 i6 300 and no matter cold or hot, tapping the pedal gives this lag (drops 150-200 rpms) and returns to idle. it idles smooth enough but when you first accelerate it does this lag then responds...any help is greatly appreciated.