3.0 hard starting, no power

[wilkin250r]

I did my research, I tried the search, I've gone through several tactics.

My 3.0 has a hard time starting, and has no power. It's possible these are two different problems, but they developed at the same time, so I feel like they're related with one root cause, I just can't find that cause. It developed slowly. At first, I would occasionally have to give it throttle to start, but not always, but now I have to push the pedal to the floor to get it to start. On occasion, when it's really stubborn, I have to pump the throttle many times (almost like an old-school carburetor with an accelerator pump, which is absurd because I know I don't have any of that) before it will start. However, once it DOES start, it seems to idle just fine.

As for power, I would estimate it has about 50hp. I literally cannot get it over 65mph on flat ground, and even the slightest uphill I have to be in 3rd gear or lower. I might be wrong, but I also feel like this developed slowly over time. Like, at one point it was difficult to go over 65mph towing an empty trailer, and now it's difficult to go 65mph at all.

It's not throwing any codes, and I removed the catalytic converter (no clogs as far as I can see), and I checked EGR, and cleaned the IAC. Fuel pressure took several cycles of the key to build up full pressure (like 5-6 cycles), but seems otherwise normal. Fuel pressure was a constant 58psi at idle, I did not check it any other engine speed. Replaced spark plugs, no change. Replaced fuel filter, no change.

What on earth could be my cause?

 

[SenorNoob]

Since you've verified fuel, how about spark, air and timing?

With it idling fine, I suggest air. Is the filter clogged? Is the warm air valve stuck on and hose collapsed? (I've seen it happen.)

 

[wilkin250r]

New air filter, and no visible obstructions in the entire air passage.

I haven’t verified spark except that I did have a loose plug wire at one point, and got a misfire trouble code. I have since fixed it, no misfire trouble codes ever since, and I don’t hear any misfire at idle. While not definitive, this leads me to believe I don’t have a spark problem.

Have not verified timing.

 

[O No 3.0!]

It sounds like you either have a weak fuel pump that cannot keep up the volume when driving. That or the engine is loosing compression causing the lack of power. It does sound like the fuel pump tho, because of the hard starting, it may have a leaky regulator too, not holding enough pressure after you shut the engine off.

 

[Rearanger]

Fuel pressure took several cycles of the key to build up full pressure (like 5-6 cycles), but seems otherwise normal.

Since you've verified no CAT blockage I would concentrate on fuel pressure. It should not take several cycles to build pressure. When did you last change fuel filter?

I would also confirm compression as one of those basic checks.

 

[mikkelstuff]

What about throttle cable stretch? Is the throttle fully opening? I was thinking these are not supposed to start with the accelerator pushed to the floor.

 

[rusty ol ranger]

Pumping the accelerator doesnt do anything on an EFI vehicle (unless you hold it to the floor to "clear" a flood situation)

The way youre describing the slow onset, no power, etc etc...id really be taking a very hard look at compression. Get a tester and check each cylinder. Espicially if its high mileage.

 

[wilkin250r]

I changed the fuel filter before I made the post.

Rusty, I almost agree with you. Pumping the accelerator shouldn’t do anything on an EFI vehicle, but it does. It doesn’t happen all the time, but when it’s extremely difficult to start, holding the throttle wide open doesn’t work, zero throttle doesn’t work, partial throttle doesn’t work, but pumping the pedal does work. I can’t explain it, but it has happened dozens of times.

I haven’t been able to monitor fuel pressure while driving.

I suppose a full compression test is next.

 

[rusty ol ranger]

I changed the fuel filter before I made the post.

Rusty, I almost agree with you. Pumping the accelerator shouldn’t do anything on an EFI vehicle, but it does. It doesn’t happen all the time, but when it’s extremely difficult to start, holding the throttle wide open doesn’t work, zero throttle doesn’t work, partial throttle doesn’t work, but pumping the pedal does work. I can’t explain it, but it has happened dozens of times.

I haven’t been able to monitor fuel pressure while driving.

I suppose a full compression test is next.

The only way possible i could see pumping the acclerator helps on an EFI is if the IAC is sticking and you crank it while you got the throttle open...but then it should die as soon as you let off.

The only other thing would be some weird (very weird) ECM issue thats telling the injectors the engines running and responding accordingly to the throttle.

 

[wilkin250r]

I cleaned the IAC, and as far as I can tell, once the engine starts, idle seems perfectly normal. RPMs are little above 1k when cold, and dropping a little under 1k when warm. Tachometer is screwy, so I can't give you accurate numbers, but the tach has always been screwy, even when the engine was running really well, so I can't see the tach as a related problem.

 

[Burnsy]

This is probably not your issue but only takes a minute to check......check plug wires for burn marks where they may have rubbed laid against hot manifold for a long time,Like months, and burnt a little spot enuf so that the wire gets exposed and the electrical current archs to the manifold instead of staying in the plug wire.....it happened to me, started as a "slight miss" then a "big miss"....

 

[Burnsy]

Ever figure it out ?

 

[helpme]

I bet your timing chain has jumped a cog. If it jumps again, it will not start.