"soft" CEL has me stumped

[mmorningstar]

a little history on the car, car is a 90LX 5.0, bought by my father in 1992 with 8K miles on it, when bought it had 355 gears, intake silencer removed but included, underdrive pulleys, and a Hurst shifter. I bought it from my father in 2005, added an X pipe, 70mm FR T-body, and EGR spacer, also added an SN95 MAF, correct number to work with ECU.

The car has a soft CEL, and according to my father has always had it, so that eliminates my mods affecting it. The CEL will illuminate inder part throttle at varying speeds, no rhyme or reason. My father said it has always done this and his dealer attributes it to the intake silencer being removed. Being that there are no codes and the car was rarely driven my father accepted that answer. I on the other hand won't It has me really puzzled, the car is in TOP condition, always maintained, always gargaged, always well cared for. I have tried pulling codes several times but have never found any other than the standard 11 for all is well, and the car runs AWESOME, it just annoys me that the CEL illuminates from time to time. It is my fun/weekend car so I don't get in it much, but I was in it today and decided to try to solve this again. I'm leaning towards the 02 sensors maybe but that really is just a guess. I guess I could try to put the intake silencer back in but I seriously doubt that is it since people have been running cone filters on these things with no CEL's. Any input appreciated.

 

[2000xp8]

Mine used to go on and off with the throttle.
It was the o2 sensors

 

[mmorningstar]

thanks

I was leaning towards the O2's but it's nice to hear it from someone who had the same issue. I'll be doing O2's soon.

 

[HISSIN50]

Ensure you have battery power to Pin 1 on the EEC. If your CEL is flickering, a code should be stored in the KAM as long as battery power is not lost from the time of the CEL to checking codes.

There are several systems which could cause a CEL only during part throttle or transient throttle maneuvers.

The air silencer is not the source of your issue, unless there is something else wrong.

Good luck.

 

[blackvertgt]

There was a recall on the 10-pin connectors between your intake and firewall, often called the salt+pepper shakers for reasons that'll be obvious once you look at them. Could be that these were never upgraded and causing intermittent errors as you accelerate and your motor moves slightly from the torque. Mine was so messed up the engine would stall completely every time I made a left or accelerated hard.
Could very well be your O2's as suggested above, but pulling apart those 10-pins and cleaning them out is free and could be the problem, saving you the time and money to change out your O2's.
Good Luck and Happy New Year!