Hello. I have a 1989 2.3 ford ranger. It has a jerk around 4th and 5th gear. Not the whole time, but periodically while accelerating. Does it worse when cold and when I put the pedal further down. I have replaced fuel pump, fuel filter, air filter, ignition coils, plugs and wires, egr valve, fuel pressure regulator, sprayed around intake for leaks and found nothing. Truck bought 4 months ago and it's driving me crazy. Any information will be greatly much appreciated. Thanks

 

Welcome to the forum

The 4th and 5th gear thing doesn't help much, I assume it doesn't have a tachometer?
Presumably its not happening at a specific RPM or it would happen in every gear at that RPM

What about the speed when it jerks?
Any relation to speedometer?

Does it happen if you are just cruising in 4th, not accelerating?

Does it happen if you do 0 to 60MPH as fast as possible?

And whats the MPG like?
Should be close to 20MPG it not better

 

Tachometer yes. Jerking usually happens more when the rpm is on the lower side but still will do it. If I am cruising in 4th it will not do it hardly much if I have the gas pedal barely pressed. 0 to 60 as fast as possible it will jerk 4th and 5th also noticed a small jerk in 3rd that way. Gas mileage I can tell has decreased since the problem has occurred. Thanks for the reply also.

 

There will be a 3 wire Throttle sensor(TPS) on the upper intake on the throttle linkage, opposite side
Unplug it
Go for a drive, acceleration will be a bit sluggish(less throttle response), but see if the stumbling still occurs

The TPS is a 5volt sensor, 1 volt is throttle closed, 4.5volts is throttle wide open, so voltage goes up as you press down on gas pedal
The computer uses the throttle sensor to see what the driver wants to do instantly, MAF(air flow) sensor is too slow to respond for instant acceleration

Long shot, so do not replace TPS until you test it
If the TPS has a "dead spot" then while you press the gas pedal and TPS is showing 2.5volts and then suddenly drops to under 1volt(dead spot), the computer cuts off injectors for that moment, the stumble, then when your foot changes TPS position injectors come back on
You can further test TPS with volt or ohm meter

 

I will try that as soon as I get off of work thanks! Also will the speed density map sensor respond the same way? As the maf for that matter

 

Drove home from work, and it drove with no issues. It is warm outside here. So it seems that the cold weather has a huge play in its jerking.

 

1989 2.3l "may" still be MAP(speed density) but I thought the 2.3ls with dual spark plugs were all MAF, but had still had a MAP just for barometer

But yes, TPS was the same for either computer software

 

Yeah I thought so also. I haven't seen a maf sensor. Any idea on the cold effecting it?