Hey guys, I am new to this forum and could use your help.

I own a 1994 Ford Ranger 2wd with a 4.0 liter V6.
The truck just turned 170,000 miles. Lately it's been giving me troubles in the morning when I first start it. It wants to shut off or have the gas pedal feathered like a carburetor to keep it running. Once the engine warms up, it tends to run pretty well.

At WOT there is no throttle response, I have to back off of the throttle to get the truck to go anywhere (engine hot or cold). Could this be a bad TPS sensor?

Also, just within the last couple days intermittently, I'll be at a light go to leave and the engine will just act up; I have to feather the throttle to find the "sweet spot" to get the truck to move. Once moving it will get up to about 15MPH and no more- like the timing chain jumped a tooth, then all of a sudden it starts running fine and accelerated much better (problem with WOT still exists).

Ever since this started happening my cruise control stopped working.

The computer is showing no codes.

The truck just had a recent tune up with a cap, rotor, and wires.

So what are your opinions?

Is it a bad TPS, bad ecu, timing chain, coil, bad injectors,ect.

I hope I am missing something stupid- I would hate to get rid of the truck.

Thanks for your help,

Brint

 

I honestly can't take a stab at what it is other than "you gotta problem". But I can say, instead of thinkin of junking the vehicle, a new engine/computer would only cost 5-700 bucks.

 

Sounds like a Mass Air.

 

Thanks for the ideas guys. With that many miles on the engine I would like to pick up a new long block anyway- but it isn't in the budget right now.

I'll through a voltmeter on the MAF tonight.

I may check to see if the cat is clogged also.

I drove it to work today with the same problems reoccurring..... just filled the tank..and got to thinking....
I hope the problem doesn't have anything to do with junk floating around in the tank and clogging the sock on the pump! I'll have to wait till the end of the week to fix that.

Any other ideas on what to look for?

Why wouldn't the cruise control work any more?

 

Hey, Same Exact Thing Is Happening To Mine. It Started After I Eliminated My Air Box To Rework The Intake. I'm Gonna Check My Plugs And Injectors. Hopefully We Can Figure This Out. K.i.t.

 

I plan to work on the truck tonight.
It's raining cats and dogs outside right now (CT). I'll let you know how I make out.

I'm tempted to go down to the ford dealership and pick up a TPS sensor.
I put a code scanner on the engine again and got "no snap throttle response", I'm not sure if this would point to a bad TPS sensor or bad signal from the ECU.

Either way the volt meter will have to come out tonight.

I'll check the convertor and replace the fuel filter to.

I'll let you know how I make out.

Good luck with your truck!

 

Yeah The Symptoms Sound So Alike. The "no Snap Throttle Response" Is Exactly What's Going On. My Buddy Was Thinking Tps Also. I've Got Rain And A Second Job So Let Me Know What U Come Up With.

 

Unfortunately I'll have to wait till Friday to pickup the TPS Sensor. The local Napa said they had 1 in stock but it turned out to be the wrong one.

I'm still planning on cleaning the IAC valve and checking the convertor tonight.
I'll let you know how I make out, but my money is on having a bad TPS Sensor- otherwise I assume the cruise control would still work.

We see what happens....... I'm looking forward to getting the truck running 100% again.

Fill you in tomorrow,

Brint

 

You also need to remember fuel system. You may have a fuel filter stopping up, fuel pump going out, or you could even have a bad fuel pressure regulator. Could be a vaccum leak, you cant check the MAF with a volt meter... It very well could be a TPS. I have also seen excess buildup on top of the fuel injectors(the screens in the tops) causing insufficient fuel delivery...

 

I cleaned the IAC valve last night and checked the converter out.
The converter looks good and cleaning the IAC made no difference.
I put a voltmeter on the TPS and the voltage was all over the place, so I believe I found my problem.

I'll swap it out on Friday and put a new fuel filter in the truck for good measure.

I don't believe the truck has a bad fuel pressure regulator because it would be running overly rich. Gas mileage has stayed the same and the exhaust doesn't smell as the engine is running rich. But I'll pull the vacuum line off it and check for gas in the line just to be on the safe side.

If the problem persists I'll check the voltage and amps draw to the fuel pump.
I wouldn't be superised if that were the issue either.

Thanks for your suggestions.

I'll let you guys know how I make out after the weekend.

I have to work on my wife's Explorer tonight- gotta fix a broken sway bar end
link and install a set of Rancho Shocks. Maybe even get the class IV hitch on.

 

Have Fun On The Explorer. Sounds Like You Checked Everything. Hope It Is Just A Tps. Easy Fix! K.i.t.

 

Well it's been a while guys but i figured out what my problem was.
The truck had a bad Fuel Pressure Regulator and a cracked cylinder head (170,000 miles!).

I changed the fuel pressure regulator and used a bottle of Moroso's Ceramic Engine Seal to temporarily fix the crack in the head while I collect parts for the V8 swap.

Hopefully the 4.0 Liter will last till the beginning of next year (So i can get it through emisions one last time).

Thanks for all your help!