Engine bogging down

[WILL-I-Am]

I recently put a motor from a 1992 explorer 4.0 automatic 4x4 into my 93 ranger 4.0 5 speed 2 wheel drive super cab . Problem I'm having is engine bogging down. PLEASE HELP !!

 

[snake]

You may have to be more specific. Might be PCM related if there were changes between those years. Check the cat, too- that'll surely cause one to bog down.

 

[RonD]

Did you swap engine sensors from '93 4.0l to the '92 4.0l.

Check Fuel pressure regulator(FPR) on the fuel rail, it has a vacuum line attached, remove this line and smell it for gas, if it smells like gas then FPR diaphragm is bad and FPR needs to be replaced.
Raw gas is being sucked into the engine via that vacuum line causing a too rich air/fuel mix.

 

[WILL-I-Am]

no I put 92 engine in 93 ranger using ranger factory everything

 

[WILL-I-Am]

Ok yesterday I put the TPS from the 93 motor on to the 92 motor it ran great for about 2 hours left home to go to the grocery store it started bogging down again!! please help

 

[RonD]

Did you unhook the neg. battery terminal when you swapped sensors?

When you remove power from a PCM for 5 to 10 minutes, it will run preset operating parameters as it relearns sensor ranges, on some sensors it takes 40-50 miles.

Just thinking out loud, so if you didn't unhook the battery try that, if you did then try it again and see if you get the same "runs good" result.

Does your truck use a MAP sensor or a MAF sensor for one of the fuel/air controls?

 

[WILL-I-Am]

I did disconnect the neg terminal before install, I also reinstalled it again same results, yes it has a maf sensor

 

[RonD]

So you tried disconnecting neg. cable again for 10min. to see if engine ran better for awhile?

Unstable MAF sensors can cause your issue:
http://www.therangerstation.com/tech_library/CleanMAF.html

 

[WILL-I-Am]

I will try it when I get home and I will get back to you