2.3L ('83-'97) 91 2.3 Three codes

[leftysdad74]

My 91 2.3 8plug acts up with skipping and missing after about 30min of driving
I'm getting 33 (tps) 41 (lean) and 88 (loss of dual plug input control)
Any suggestions on where to start??
That 88 has me a little stumped
Thanks in advance

 

[RonD]

Welcome to TRS

The "skipping and missing" are of course misfires
Misfires cause Lean codes

So once you address the misfires the Lean code should go away

Warm up the engine first
Shut it off and unplug the 3 wire connector for the Coil pack on Drivers side spark plugs, pull it back far enough so it can't Arc back to its plug in
Start engine
Should run smooth if all 4 spark plugs on Passenger side are working
This 2.3l engine ran on 4 spark plugs from 1974 to 1988 just fine, in several Ford Models

If engine is struggling to run on the 4 passenger side spark plugs then there is a problem with spark plugs, wires or the coil pack, but...........................
The most common complaint in the spark system for 1989 thru 1994 2.3l's was the ICM(ignition spark module), located on the front of lower intake behind the fan, it needs lots of cooling
And this could be were code 88 is coming from

So you may want to change the ICM just on speculation, it needs a good ground, the 3 screws, so make sure they are rust free, also needs heat sink coating on the back to keep it cool
Inspect the wires on both connectors, they can get brittle from heat and age

You can test the other coil pack and its 4 spark plugs but you have to unplug the coil pack after the engine is running
Only the passenger side coil pack is used for starting, but once RPMs are above 400 the drivers side coil pack come on
Use insulated pliers to unplug the 3 wire connector on passenger side coil pack
As said engine should run just fine on the 4 drivers side spark plugs
Dual spark plugs add extra power, so there is no alternating, both spark plugs fire at the same time


Unplug and plug back in the TPS(throttle position sensor) to clean its contacts
See if code comes back


Replace O2 sensor, O2 sensors are the ONLY sensor that "wears out", 12 years or 100k miles and they start to run out of the chemical that detects Oxygen in the exhaust, and they can/will throw False Lean codes after that
Older O2s cause Rich running(false lean) so MPG goes down, and the rich running fouls spark plugs