My only truck has an intermittent timing problem. 2.3 liter, 1993, 2 wheel drive, 5sp

[used to be a chevy man]

My daily driver has an intermittent problem that is seemingly ignition or timing related.
I can start it up and drive it around just fine most days but sometimes it acts like it jumped time then for no reason starts running right again sometimes within a minute sometimes not for hours. It doesn't always die when this happens and it usually happens when it is hot but it will do it cold. It almost never does it in the winter. I've had the problem since I bought the truck a couple years ago but it's getting worse.

Here is what I have tried so far.

New exhaust (it was burned out and chunks of busted up honeycomb were plugging up the muffler)

Verified fuel system is ok
35 to 40 psi when the problem is happening (or not)
New relay/cleaned sockets
Changed filter
Dropped the tank and checked hoses
Injectors are working
Checked the fuel pressure regulator OK

Replaced spark plug wires

Checked all vacuum lines OK
Plugged off half of them while the truck was running to make sure the auxiliary components were not leaking. Still had my "timing" problem after doing this

Changed idle and TPS sensor

Replaced aftermarket ICM with Motorcraft ICM

replaced EEC

Cleaned egr, verified plugs

Cleaned CPS, cleaned the marks it reads off of

Replaced both coil packs, cleaned sockets, verified all 8 plugs fire, one that I replaced was actually bad but replacing it did NOTHING

Cleaned MAF and manifold pressure sensor

Cleaned o2 sensor (it wasn't that dirty)

Replaced the air filter (I noticed it didn't seal well and was letting dust in the intake. I fixed this yesterday)

replaced timing belt and tensioner. The tensioner was wobbly but the belt seemed ok. It had not jumped time. This is the only thing that has made ANY difference but has come nowhere close to solving my problem.

I have not replaced the spark plugs because half of them are really hard to get to but I plan on it

I have kept up on all the fluid changes

This year does not have a cam sensor

This year does not have a distributor and is fuel injected

I have never overheated the motor

When I bought this truck it was very clean and looked like it was only used for city driving 130xxx miles at the time. It now has 165xxx miles on it.

The only modifications I have made are the exhaust, a 250 amp high output alternator and a 2400 amp 110 Wh power cell. I no longer have an amp in the truck to go with these. They have not made the problem better or worse. I was having the problem before I put these in.

Until I went unplugging stuff the other day while I was running the check engine light was not on but here are the codes it throws anyways

522
539
629
566
These are tranny codes from having a computer out of an automatic in a manual truck (I was planning on switching to auto but didn't. I still have ALL the parts to do itthough). One I fixed, the e-brake switch was unplugged and one is an a/c code because I unplugged the a/c

224
223
These are related to spark and I think are a result of messing with plugs while the engine is running but they may be relevant to my problems.

 

[used to be a chevy man]

Today i have tested my coils with an ohm meter, gapped my spark plugs and replaced an auto zone coil pack with a motorcraft one. jiggling the coil pack plugs has got my check engine light to shut off. still having the same problem but all this maintenance is making my truck run better and better!

 

[feellnfroggy]

Sounds like the MAf or related component is beginning to go bad.

 

[Chris_1]

How well does it run if you unplug the MAF ?

 

[used to be a chevy man]

It runs worse if I unplug the MAF sensor. It is not the same kind of stumbling problem I am having. Also the check engine light comes on when I unplug the MAF sensor.

Today the problem is worse with more frequent stumbling and an intermittent check engine light which I did not have before. I'm going to try to read the codes myself and see if it throws any new codes.

I am led to believe this is a CPS on its way out because I have read some forums about bad CPS and it says they cause all the problems I am having down to a tee. People that have replaced the CPS also say theirs tested good but was still bad under driving conditions.

I don't know how to test a CPS in my car but this info would be helpful. ( I do know where the CPS is located and I know there is no cam sensor on this car)

I have attached a light to my injector 1 circuit. I plan to see if I get an abnormal pattern or no pattern at all while the engine is stumbling. This will let me know if the problem is not isolated to ignition (spark) right?

Also I took my ICM in to get tested one more time. They ran it 6 times and it was very hot (I'd guess 150*). Anyway it passed all 6 times so I'd say its safe to say I have eliminated the icm correct?

 

[used to be a chevy man]

One more thing. I replaced the two wire temp sensor responsible for thinning out the fuel mixture once the engine is warmed up. It idles differently now but still stumbles frequently.

It seems to run the best without this sensor plugged in but the check engine light comes on that way. I am guessing it runs rich without this sensor.

Plugged in or not I still get the stumble problem.

Also note very few 2.3L ford rangers have the same temp sensor as the '93

 

[used to be a chevy man]

So today i followed the instructions found here <a href="http://easyautodiagnostics.com/ford/ignition_module/2.3L/ignition_module_test_1.php"> to test the CPS and under cool conditions it passed. tomorrow we try under stumbling conditions

 

[used to be a chevy man]

<a href="http://www.therangerstation.com/forums/showthread.php?t=118385">this guy had the same problem and fixed it by replacing the ICM that tested good 10 times so.... I guess skip the crank sensor and replace my "good" ICM????????????????

Someone please reply.

 

[Andy D]

Uhhmn, It is too bad that the spark plugs are a PITA to R+R. That is the first thing I look at when I am diagnosing a mis fire.

 

[used to be a chevy man]

I'm pretty sure im not getting a misfire. All 8 plugs fire its just hard to catch it when its running rough. i did notice the exhaust stroke fires in an odd pattern but that might be normal. someone else said they noticed it too.

By the way what is PTIA and R+R?

Ive already pulled all 8 spark plugs and they were ok. i gapped them before i put them in

 

[Andy D]

Pain In The A$$, Remove and Re place

 

[used to be a chevy man]

Still having the problem.
Since my last post I:
Tested and replaced the MAF (again) air temp sensor(didn't fix anything)
Found that the vacuum pot was leaking (idles better but didn't help)
Tested the CPS under a no start condition. Both Hall effect generators pass
Replaced some bad ends to my coils (did not help)
I was going to replace the icm but they tested it 6x in a row and it passed (was fairly hot)
I noticed that the truck is slowly emptying the radiator resivior. I'm thinking maybe a cracked head or bad gasket. I'm going to try some aluminum stop leak tomorrow and keep everyone updated.
I have a throttle body I'm going to clean up and swap out when I get the time and Im going to replace the egr and the little vacuum attenuator attached to it but by now I'm just shooting in the dark.
Thanks to anybody who helps.

 

[used to be a chevy man]

Still haing the problem

Im not sure if anybody is still following this post but just to sum it up all my electronics are good. i noticed it uses coolant so this weekend im going to try and replace the head and see if the problem clears up (knock on wood)

 

[stuntsunltd.]

timing issues.

Have you tried having the fuel injectors cleaned. If a previous owner drove with a bad fuel filter or bad gas it may have allowed some buildup in the injectors leading to an intermittent poor fuel spray. Also did the problems begin before or after you swapped in the computer from an automatic? if after put the old computer back in and see if that helps.

 

[BRUTUS_T_HOG]

Im not sure if anybody is still following this post but just to sum it up all my electronics are good. i noticed it uses coolant so this weekend im going to try and replace the head and see if the problem clears up (knock on wood)

When it acts up put your hand on the EGR tube and see if it is hot. If so the valve is flowing exhaust.

What exactly is it doing? Runs rough? Lack of power?

Do you have a tachometer? Does it drop out?

Can you attach a timing light and drive around to see if it drops out?