3.0 undrivable

[Ranger305]

Truck: '92 Ranger 3.0, 5spd, 220k miles

Symptom: Started a few weeks ago would occasionally buck while driving on interstate @65mph. Quickly progressed to occasional bogging at any throttle range. Now, it wil idle ok 80% of the time, but will still bog every couple minutes. If I give it throttle with no load, it will run ok for exactly 3-4 seconds, then bog. Seems worse when raining or humid. MPG down 5-8mpg, truck smokes a bit at startup. Throws CEL, usually MAF related.

Items replaced/maintenance lately since the problem started: plugs, wires, cap, rotor, maf, fuel filter.

Diags so far: used an led to check the signal from the pip and TFI, ok but a little shaky from the pip when the bog starts. Fuel pressure within spec. Checked all connections and wires I can find for shorts, breaks, etc. Nothing so far. Only issue found was a vacuum leak on the fuel tank side of the carbon canister by the rad. TFI checked on machine at Autozone, tested ok.

I'm running out of ideas and I'm trying not to throw parts at it blindly. Anyone have any ideas?

Thanks.

 

[AgPete139]

Hey man, and welcome to TRS.

It sounds like a crappy situation. I have 2 suggestions that may work for you, especially since it has 220K miles!

Fuel lines do clog, despite fuel filters and whatnot. Run half a can of Seafoam in your gas tank when it's about 1/4 full. The petroleum distillates & chemicals should clean your lines pretty good, especially if they are badly gunked up. It's like an enema for your truck!

The second process is simple enough, and also effective. It cleans your vacuum lines, mainly the ones closest to the intake manifold and some of the emissions lines. This requires about a full can of Seafoam as well. Locate the brake booster, and pull the thick vacuum hose that goes to your intake manifold. While your truck is warmed-up & idling, slowly pour the can into the hose, and keep the engine running (without letting it die).

...once youve poured about 2/3 of it in, shut off your truck and let it sit for 15 minutes. Drive the truck afterwards, and all the accumulated shit will come out of your tailpipe in smoke form (this is standard & normal).

This also seriously works. I'm not a big advocate of "miracle products" & advertising, but this is actually a viable solution.

This eliminates a badly crusted system.


Good luck.

 

[Ranger305]

Found it!

Found most of, if not all the issue. Replaced the fuel pressure regulator and it is purring like a kitten. Ended up pulling the plenum and fuel rails, so I pulled the injectors and sprayed them as much as possible without disassembly, and cleaned the intake runners as best possible with it on the truck. Checked the fuel pressure and it is a steady 30psi, so the pump may not be 100%. Deciding on whether to change it or not. Once I sort that out, I will be pouring copious amounts of seafoam down it. I seem to buy it a few cans at a time when I find it on sale for my boats. Thanks for the assist!

 

[Ranger305]

Found the rest. Found that the MAF sensor I put in 3 weeks ago was bad and had 0 voltage output. Final tally: Fuel Pressure regulator, 2 MAF's, new fuel pump (wanted working gas gauge and to eliminate the old pump as a possibility), cleaned the injectors and plenum.

Now to clean the plugs off from the fouling and flush the radiator to get back to where it needs to be. 1/4 million miles, here I come.