95 B2300 2.3L miss

[Swoopy]

Hello all.
1995 2.3L 478,000 miles! original motor (never opened) and rear brakes!
2 trannies, 1 replacement clutch and front rotors twice and pads several times.
Runs great for the miles, still got 23 mpg! Extended cab 2 WD 3.91s
Runs a little softer and nice until yesterday.
Started to miss then corrected drove home 10 miles.
Next day ran great then when warm after 8 miles happened again then restored for about 3 secs than back to missing. Drove 13 miles. Went for a test run later that night, cold and after warm less then 3 miles and it did not miss. Next day, 5 miles ran good (normal) and than miss returned.
Ya I know, I'll get the OMG, but only 1 timing belt change at 160K.
Changed the 02s air, fuel and fuel pump at 250K. many with air and oil changes.
plugs 3 times and new radiator.
It will run tight till it gets about 5 miles or so, warm, then misses.
I know the T-belt needs to be changed and perhaps the tensioner.
There is a clicking noise louder then normal at front valve cover. Could it be cam sensor ticking?
It sounds like loud values or perhaps a fuel injector clack?
If it were mechanical, it would be constant and not run good when cold?
I'm thinking, timing or a sensor? But timing how when it runs good cold?
Could it be a closed loop runs ok, than data input when warm and misses?
I'm perplexed. Cat may be full also with that many miles.
Well been reading here and there on this site and found great information, and more then a few nice trucks.
Truck served me well, no regrets.
Purchased a T-belt, can sensor, and water pump seemed like a good idea as the miles are high, but no issues.
Didn't run codes but will buy a OBDII tool.
Stumped. Any thoughts would be appreciated. New motor instead of repairs?

 

[RonD]

There have been some members with the Limas that had intermittent(to start with) issues that were caused by valve train issues, rocker wear(ticking) was not riding squarely on the Cam, so hit and MISS issue, broken valve spring, worth pulling the valve cover to check it.

Both spark plugs fire on each compression and exhaust stroke, but a coil issue could still be the problem, especially if its not a full time miss.

Coil packs can be tested with an OHM meter, it can't confirm coil is 100% but it will show if it is bad.

Not sure if the '95 injectors are still batch fire, if they are then fuel shouldn't be the issue.
If it's sequential injection then could be a sticky injector.
Either way a can of seafoam in the gas tank wouldn't hurt, I do it once a year since I buy regular gas that doesn't have additives.

Clogged Cats usually show up first at higher RPMs and a loss of power when trying to accelerate.

 

[Swoopy]

Thanks for the assist.
I did a code read and it gave me the suspect cat, o2s and egr, but the miss was not known especially defined to 1 cylinder. Miss happens only after warm, after 5 miles or so. At first it would go away, than after 10 miles and has worked it's way down to less than 2 miles. Seems to be either ignition or injector. Spring or broken or worn item would not switch on right? After the truck sits, it does not miss, drives great than warm and the miss starts.
I agree on test the coil as another told me of that. Good point on injector, I'll track it down as whether batch or not. Thanks,

 

[Swoopy]

Test coils. Front had .6 primary and 12.54 and 12.69 and secondary had .6 and 12.75 and 12. 74 ohms. Hayes says primary should be less than .5 and across cap towers 13 to 17 ohms.
mine is under on booth coils which have 475,000 miles. still working on miss. will pull valve cover, to check top side, but is there any way to test fuel injector?
Thanks, Dave.

 

[stateranger]

Listen to each injector through a piece of rubber hose. If one is sticking it will be quieter than the other three. Do a fuel pressure test with the regulator vacuum hose attached then unattached.

 

[RonD]

Coils reads fine, probably your OHM meter reading high.
Next time your at a parts shop have them pull out a new coil and test it with your OHM meter.

 

[Swoopy]

Not a bad idea to listen with hose.
Will check new coil, but my meter is new and auto range. Could still be questionable.
With that many miles and cycles to the coils, I am almost sure it is them.
ICM or crank sensor, but it runs good then fumbles and stumbles...Swamy reference.
So while I don't like replacing parts that test ok, I could see replacing these.
Would an injector run good then snap not work?
That's why I keep going to coil.
Perhaps O2s as someone stated do not come online until after warm.
With 475,000 miles, I don't want to throw money at a sink hole.
thanks guys for assistance, I'll go over again today.

 

[Swoopy]

Well got it.
had me stumped as it would run cold than miss after a few miles.
Put a new primary coil on and it ran better and than wouldn't ya know it a miss after a few miles.
So plug #1 plug, looks good, test spark, yep good spark.
Leave plug out and start to see if it had gas build up, no gas..hmm.
Pull wire at coil #1 and no difference when running, still a miss.
Pull electric plug at #1 injector and no difference.
test for pulse with a 12 volt small interior light and it had a pulse, but basically remained on.
so it must be injector.
Replaced the injector with help from you tube{love me some you tube instruction, fixed microwave door} and left manifold in place. just removed the fuel rail bolts, 2, and pulled rail back enough to pull out #1 injector, replace and darn if it didn't run smooth.
thanks al for the assistance.
a buddy said that the injectors usually go out close together so get ready, is this true?
With 475,000 miles, I'll be doing it again?

Same guy has 19 # ford 302 injectors of similar age, will these work?

thanks again, I'back to chores, dump runs etc...