weird power problems while cruising

[puty72]

1989 ford ranger 2.9 4x4 automatic 4.10 gears.

things that are new or a year old : fuel pump, fuel filter, plugs, wires, cap n rotor, o2 sensor , catalytic converter, IAC, TPS, ECT, air filter, ignition module of the distributor. oil level is good no leaks or signs of wear. Transmission fluid is good level and color. shifts fairly smooth for being 21years old. NO codes pulled check engine light is off.

I tried for answers on here for the past two years and it just lead me to buying more parts and not getting the results I want. Anyways sometimes my truck idles smooth at start up and other times it sounds like its idling rough but the rpms dont fluctuate. I ran injector cleaner threw it many times and still no difference. Also my truck seems to be shifting threw the gears pretty smoothly for its age but it runs the rpms very high 4grand at 60mph. it also sucks gas pretty good bout 180miles to the tank. its shifts into overdrive pretty smooth but it feels likes its buckin when cruising in od. The engine makes almost the same noise as if it was a manual tranny in the wrong gear like that fluttering sound. Im not sure what it is. the engine has 114k miles on it for being 21yr old which isnt bad and the oil always looks good so im not sure what it is.

 

[RustedRanger]

I went through something like that......putting on parts and still not fixing the problem. The best thing I did was to have a friend who does mobile auto-electric diagnostics put his computer on it. Not a code reader but a diagnostic computer,he found several problems I probably not have found and would have replaced other stuff I didn't need.

 

[Tedybear]

1989 ford ranger 2.9 4x4 automatic 4.10 gears.

things that are new or a year old : fuel pump, fuel filter, plugs, wires, cap n rotor, o2 sensor , catalytic converter, IAC, TPS, ECT, air filter, ignition module of the distributor. oil level is good no leaks or signs of wear. Transmission fluid is good level and color. shifts fairly smooth for being 21years old. NO codes pulled check engine light is off.

I tried for answers on here for the past two years and it just lead me to buying more parts and not getting the results I want. Anyways sometimes my truck idles smooth at start up and other times it sounds like its idling rough but the rpms dont fluctuate. I ran injector cleaner threw it many times and still no difference. Also my truck seems to be shifting threw the gears pretty smoothly for its age but it runs the rpms very high 4grand at 60mph. it also sucks gas pretty good bout 180miles to the tank. its shifts into overdrive pretty smooth but it feels likes its buckin when cruising in od. The engine makes almost the same noise as if it was a manual tranny in the wrong gear like that fluttering sound. Im not sure what it is. the engine has 114k miles on it for being 21yr old which isnt bad and the oil always looks good so im not sure what it is.

I'm having issues of my own. However what you've described matches what my ol' girl was doing a couple of months ago. Suggestion: Start the truck..then turn the truck 'off'. (stone cold...this involves fuel) Remove the vacuum line at the intake manifold that feeds the fuel pressure regulator and let it hang loose for a few minutes. Here's the logic: The system will pressure up to about 35-40ish pounds of fuel pressure. Now if you have a pinhole leak in the rubber guts of that regulator? While driving you'll get a sudden small dump of raw fuel into your intake manifold. This throws off your air/fuel mixture and the truck's ECM tries to compensate for it. The result is a surge that feels like it's "Bumping" the engine.

By doing the test? The system will have fuel pressure on one side of the rubber guts---and any leakage? Will show up as a small drip drip drip out the vacuum line. Please do not do this test with a hot engine or running...

S-

 

[gaz]

"puty72",

Did you figure this out?