afoutch

I have a 1995 F150(80k), auto trans with inline 4.9l 6cyl that intermittantly stalls and bucks while driving. It doesn't do it all the time. You can be driving 55mph and it will feel like it is stalling and/or bucks and jerks. I have a tendancy to pump the gas but can't tell if that does any good. Usually, I will have to pull over until it clears itself. So far it hasn't stranded me but I feel like I better get the problem resolved before it does.

I have taken it to a repair shop to have it hooked up to a computer but nothing came up. After a few suggestions, I replaced the following:

-Spark Plugs
-Plug Wires
-Dist Cap and Rotor
-Fuel Filter
-MAP Sensor
-EGR Valve
-Air Filter

These were all still original parts when I replaced them. Replacing these parts did not fix the problem. I'm not exactly a mechanic so if anyone has any suggestions, please keep that in mind, but am not afraid to tackle a do-it-yourself job and save some money.

Here are some other suggestions that I have been told but not done them yet.

-Have Fuel pressure guage put on it.
-Replace throttle position sensor(not sure where it is located)
-Vaccum leak

I'm hoping someone out there has had the same problem and could help steer me in the right directions.

BIG D

I would definitly have fuel pressure checked,the throttle pos. sensor could also be a problem but you would need a scanner to check and see if it is failing or not,it sounds like it is fuel related(pump)and not so much the tps.If you get a chance to have scanned,check the coolant temp. sensor reading too,usually the temp. sensor only causes a no or hard start problem but you never know.

wde3477

Hmmm, tough one.

Make sure the MAP sensor line from the manifold doesn't have any leaks or cracks in it.
From my experience - a TPS failure will result in the bucking thing when the throttle position is changed, but not at steady-state. The computer should've been all over this as far as throwing a code.
Perhaps you have an intermittent ignition system problem - such as coil, stator pickup, ignition module, wobbly distributor shaft, etc.

Stick with it, methodically eliminate the things you know it ain't - you look like you're well down that path. Suspect this is going to be one of those things that you pull your hair out over, then when the solution is found - D'Oh, should have thought of that earlier.

dockman

I have had the same problem and have been working on it also. Did the same as you, basically, I gave it a good tune up (plugs, cap, filters, etc) to eliminate all of that. i believe that it is down to the TPS, though not likely, and the O2 sensor. If I get it fixed first I will let you know, please do the same.

afoutch

Will do dockman. Have you had the fuel pressure checked? I haven't done that yet but I expect it to read okay until it starts acting up again.

jparker223

Afoutch,

I had the exact same problem on my '88 Ranger. Like you, I received the same list of instructions: "Spark Plugs, Plug Wires, Dist Cap and Rotor, Fuel Filter, MAP Sensor, EGR Valve,Air Filter." I took care of that list as well as the throttle pos. sensor. I even bought a new ECM (computer). In the end it turned out to be a bad fuel pump. I dropped the tank replaced the whole unit (pump, filter, and sending unit) as well as the in-line filter on the frame rail. This did the trick. Hope this helps.

afoutch

Thanks for the input. Replacing the fuel pump looks like the road that I am heading. I have a fuel pressure guage hooked up to the schrader valve so I can read it next time is starts stalling. I expect to see a drop in the pressure. It's been awhile since it has done it but I wanted to make sure of the fuel pressure before I bought a new pump.