help needed on ford ranger "87"

[donaldbuckley]

working on a 1987 ford ranger surges and hitches and shakes and shutters . Feels like it is getting gas and then not getting gas then getting gas and then not getting gas again. most everything has been replaced on it. Confused can not figure it out. Please Help!! BUCK

 

[alwaysFlOoReD]

Hi, welcome to TRS.
Can you give some detail about your truck ie; motor, trans, gearing, tire size.
How many miles?
What did you replace?
Does this happen all the time or when it's cold or hot?

Richard

 

[RonD]

MAP sensor on firewall(toward passenger side) controls Fuel/air mix.
It has a vacuum line, find it and follow it to MAP location, check line for cracks/leaks, also check MAP end of line for goo, per Adsm8, that would mean replace MAP.
Check electrical connector as well.
MAP = Manifold absolute pressure, it tells the computer how much incoming air there is so computer can pick the right mix.

There is no "test" for MAP sensor, is sends out a frequency, not a voltage.

Check fuel pressure regulator(FPR) it is on the fuel rail it also has a vacuum line, check that line for gas or gas smell, it you have some or smell it replace FPR, it is leaking and raw fuel is being sucked into the intake.

Check fuel pressure at rail, 35psi is what is expected.


How old is the exhaust system, clogged up Cat converter limits exhaust flow so limits intake flow, usual symptom is good idle but loss of power as RPMs increase