• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

96 2.3 very troublesome miss at idle


twindad

New Member
Joined
Mar 22, 2014
Messages
3
Reaction score
1
Points
0
Location
near Tupelo, MS, USA
Vehicle Year
1996
Make / Model
Ford
Engine Size
2.3
Transmission
Manual
Hi everybody,
I've been working on a 1996 Ranger 2.3 5 spd reg cab truck that I bought for my son about 3 weeks ago and I'm having trouble getting it to run right. It has a rough idle, not too bad cold but it gets really bad after it warms up and idles down- lower rpms=worse miss. I think I can also feel the miss sometimes in different gears, usually at lower rpms in 4th or 5th. What I have tried so far to fix it is:
1. CEL on- codes related to missing downstream O2 sensor and inoperative canister purge valve found by autoparts store employee with code reader. NO codes for any engine miss, lean, or rich, etc.
Cat is also missing-had downstream O2 sensor installed in exhaust pipe and reset PCM- only code for inoperative canister purge valve came back after i cleared codes.
2. two cans of Seafoam in two half-tanks of premium gas. I noticed a new fuel filter had been installed before i got the truck.
3. cleaned MAF sensor with MAF cleaner. truck has new air filter. engine idle changes when i unplug MAF. tightened all air intake connections- no leaks
4. cleaned original IACV then tried a new IACV- no change in rough idle with either one, but idle will change when either was unplugged
5. applied vacuum to EGR valve- engine stumbled as EGR valve opened
6. new gasket between upper and lower intake manifolds. also sprayed carb cleaner all over gasket and vac hose areas- no indication of vacuum leak anywhere- vac gauge reads 18 in hg and steady
7. new Motorcraft spark plugs- OEM recommended ones gapped to .042". old Autolite plugs all looked good and tan, nothing fouled, wet, or black
8. new spark plug wires
9. new rear coil- old coil had the inside of two terminals partly burned away and wouldnt fire on those towers. old front coil tests okay when ohmed out- primary wire reading .9 ohm and secondary about 13.1K ohm I think. all wires from PCM to coil packs test as good and continuous. good grounds to coil bracket.
10. fuel injectors are all clicking as they are activated- heard them thru a stethoscope. Injector coils ohm out around 15 ohms i think. Injector wires to PCM are good and continuous. connectors all plugged onto injectors good
11. dry compression test- cyl1-131psi cyl2-155 psi cyl3-180psi cyl4-150psi
12. wet compression test- cyl1-140psi cyl2-170psi cyl3-185psi cyl4-175psi
the rings are a bit worn, NO smoke out the tailpipe, NO bubbles in radiator
13. new radiator cap to stop top rad hose from sucking together- plenty of antifreeze in radiator- engine runs on cool side, takes awhile to warm up
14. new muffler was put on truck right before i got it- a dollar bill held against the tailpipe will periodically suck back against the tailpipe
15. no hard data, but the gas mileage and the power are not what I expect this truck is capable of
16. fuel pressure- KOEO test showed a jump to 40 psi and an immediate fall to 0 as pump quit running, but KOER test showed 30 psi steady which jumped to 39 psi steady when i pulled the vacuum line off of the fuel pressure regulator
17. timing light tests- with my old timing light on the #1 exhaust plug the timing mark was jumping around between the 0 and 20 marks. i began to notice dark spots in the strings of flashes, which i think indicate an intermittent miss on that plug. i tried the timing light on all of the 8 plug wires and saw dark spots where regular flashes should have been on all 8 plugs. NO random misfire code has been set. the dark spots coincide with the engine sputters as it misses. the two wires which have the most dark spots in the timing light patterns go to the two rear towers on the new rear coil- the old rear coil had the insides burned out of these same two towers.
I'm running out of time and money with this thing. What else can i check or do to it to fix the miss?
 


Rock Auto 5% Discount Code: F9A1A579ACFAD1: October 1st, 2021

twindad

New Member
Joined
Mar 22, 2014
Messages
3
Reaction score
1
Points
0
Location
near Tupelo, MS, USA
Vehicle Year
1996
Make / Model
Ford
Engine Size
2.3
Transmission
Manual
Finally found the cause of the intermittent miss and rough running at idle- after removing the upper intake/throttle body as a unit, releasing the fuel pressure and removing the injectors, I found a little piece of black plastic caught in the tiny screen in the #1 fuel injector. I hooked each injector up to my battery to cause it to open, then I sprayed carb cleaner backwards through each injector (backflushing) to clean them. After reassembling everything and running it, I have never heard this 2.3 run smoother.
 

94 lngbd

New Member
TRS Banner 2010-2011
Joined
Nov 24, 2007
Messages
862
Reaction score
7
Points
0
Age
56
Location
Lakewood,Wa
Vehicle Year
1994
Make / Model
ford
Engine Size
2.3l
Transmission
Manual
that sounds like what my 2.3 continues to do at idle. I may have to pull my injectors & back flush them. Any order to hooking them up to battery or does it make a difference?
 

RonD

Well-Known Member
Joined
Jun 2, 2012
Messages
20,130
Reaction score
3,952
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
Finally found the cause of the intermittent miss and rough running at idle- after removing the upper intake/throttle body as a unit, releasing the fuel pressure and removing the injectors, I found a little piece of black plastic caught in the tiny screen in the #1 fuel injector. I hooked each injector up to my battery to cause it to open, then I sprayed carb cleaner backwards through each injector (backflushing) to clean them. After reassembling everything and running it, I have never heard this 2.3 run smoother.
Wow, that was a hard fix, very good job in tracking that down :icon_thumby:
 


Top