Hey guys i have a really bad problem. We got the car and first things first i did a normal tune up. Plugs,wires,cap,rotor,fuel filter, all the basics.
Well about a month later i snagged off the exhaust. sounded great so i kept it that way wasn't loud just had a nice low rumble to it. Yes i also thought there wouldn't be enough back pressure but i checked and 4 cats is enough. Ok so about 3 months ago back in Nov. The car started having a really bad idle issue. It would almost die out then save it self and come back. This was of course after i changed the timing. Well so 2 days went by i tried idle relearn and that didn't help. Turned it back to 10 just like it was to start with. Well so i go back down a octane rating to 91. i was using 93 while on 14 deg timing. So the idle problem is still there. First things first i clean the MAF, IAC.

After that didn't work i began to think i had a HAS problem. so i changed it. That didn't help. So next thing i did was run a bottle of sea foam through. Well that cleared out alot of crap. I did that 3 more times. Checked everything again. This time i thought the MAF was bad so i tried replacing it. Didn't work Tried replacng the IAC didn't work, Replaced the Dist all together didn't work. Ok so i am at a lose here. I pulled the plugs cleaned them put new wires on. All the stuff i am doing to the car has been Motorcraft stuff nothing cheap. i luckily had a connection at work and got 99 % of it free. I have had 3 different mechanics look at it. We checked all the TPS,IAC,MAF, all the voltage readings, O2 sensors, They were all functioning correctly. I mean 3 different people can't figure it out that were all Master ASE Techs and had been working on these type of fords for the majority of there career.

So now i am at a lose for words. The car is pinging on 93 now. I hope that was just the gas i got. I usually use Shell and didn't so i hope thats the problem. The car will idle very irractically. It will even die out now on occasion. More then once or twice if i am not on the gas. I made sure the wires were run parrallel checked the plugs. I am going to go check the plug gap again today. My fuel pressure while at idle is at 30psi when i rev a split second it will jump to 40. I turn the car off it will hold 38psi in the fuel rail.

Sorry for the typos

 

Any modifications to the engine?

 

Seems like replacing all those sensors would have done somthing....You've done alot i wonder what it is?

 

Its a Ford, what did you expect?

that aside, I wonder what your problem is, is it 5-spd or auto?

 

Any chance you have a vacuum leak? If you have a vacuum leak it can idle rough and can cause hesitation (to teh point of stalling) when at idle and when accelerating from a stop. A vacuum leak also lets unmetered air into the engine...meaning that you can run lean and your computer would never know it because the air is unmetered. And running lean due to unmetered air would cause detonation / pinging.

 

+1

 

+1
When i was working on my moms toyota a hose came off and i didnt notice, When i got it runnign finally it would run like crap and stall every time i let the gas off. When i brought it to a friends right away he noticed the hose was off, problem fixed immedietely.

 

I have checked every possible Vacumn leak there could be and any hose. There are no mods to the motor at all. It's stock besides the snorkal i took off. I have probably used over 3 or 4 cans of carb spray trying to locate any vacumn leaks.

 

Did u check all connections under the car .... o2plugs , tranny wires?

 

did u check the egr mayb its stuck open and causing it to stall