2.5L ('98-'01) 2.5l won’t rev past 3000rpm

[johnnyboy110]

I've had this truck for about a year now and it was running great. All of a sudden it runs like poo. Down on power and it won’t rev past 3000rpm. It seem ok until it gets close to 3000 rpm. The truck starts up every single time. If you free rev it, it will sometime stall at idle. If it doesn’t stall then it runs rough for a bit then smooths out. Fuel pressure is good(65-72psi) and the pump and filter have been replaced. I checked spark and all 8 are firing. There are no codes and everything seems to be fine on live data. I checked the air filter and exhaust system for clogs. No probs there. I even cleaned the mass air flow sensor. I attached a video of some of the parameters. Not sure if it will come though.

 

[rusty ol ranger]

I've had this truck for about a year now and it was running great. All of a sudden it runs like poo. Down on power and it won’t rev past 3000rpm. It seem ok until it gets close to 3000 rpm. The truck starts up every single time. If you free rev it, it will sometime stall at idle. If it doesn’t stall then it runs rough for a bit then smooths out. Fuel pressure is good(65-72psi) and the pump and filter have been replaced. I checked spark and all 8 are firing. There are no codes and everything seems to be fine on live data. I checked the air filter and exhaust system for clogs. No probs there. I even cleaned the mass air flow sensor. I attached a video of some of the parameters. Not sure if it will come though.

No video.

Possible timing belt issue?

 

[alwaysFlOoReD]

I believe there is a max 3,000 rpm limit when in park or neutral. Otherwise check compression.

 

[johnnyboy110]

I believe there is a max 3,000 rpm limit when in park or neutral. Otherwise check compression.

It’s 3000rpm full throttle in any gear. Also, if I just free rev it, it will die as soon as it comes down to idle unless I feather the gas to keep it running.

 

[johnnyboy110]

No video.

Possible timing belt issue?

I was also thinking this and when I tried to check the timing marks the F-ing steering pump is in the way. Why the hell would they design it to where you have to remove the pulley??

 

[rusty ol ranger]

I was also thinking this and when I tried to check the timing marks the F-ing steering pump is in the way. Why the hell would they design it to where you have to remove the pulley??

Because its ford

 

[scotts90ranger]

There's a rubber plug in the timing cover, t hat is where the timing mark for the cam pulley is, doesn't help on the cam sensor pulley location but if you turn the crank to TDC and know it's compression I don't remember if it's the diamond or triangle mark that will line up in the hole but there's a mark on the rear timing cover that matches.

 

[rotaryknight]

run the engine with only the exhaust manifold. If it runs fine, the catalytic convertor is clogged.

 

[stmitch]

Vehicle Speed Sensor failure will limit rpm and speed to around 30 mph

 

[johnnyboy110]

Vehicle Speed Sensor failure will limit rpm and speed to around 30 mph

It will go faster then 30mph.

 

[johnnyboy110]

There's a rubber plug in the timing cover, t hat is where the timing mark for the cam pulley is, doesn't help on the cam sensor pulley location but if you turn the crank to TDC and know it's compression I don't remember if it's the diamond or triangle mark that will line up in the hole but there's a mark on the rear timing cover that matches.

I changed the timing belt. All the mark line up.

 

[johnnyboy110]

So I replaced the timing belt and the mass air flow sensor. Did nothing. Still hard core miss. It actually threw a p0301 code but no check engine light. I checked all the wiring and it looked like the bolt to the ecu was not threaded all the way in. I cleaned up the treads and put some dielectric grease on the plug. It seemed to help and the truck was running great. This morning I got in it and she was running great for about 5min then back to shit, not raving past 3000. Parked it and gave it a quick free rev and it was fine. I don’t know what else to do but engine swap it.

 

[scotts90ranger]

Is there a rattle like the catalytic converter is broken possibly? If it's missfired like mad and melted the converter into a wad that broke up and is plugging the outlet or something that would sometimes limit exhaust flow, unless a capacitor in the ECM died this isn't making any sense... I'd hate to suggest throwing money at stuff, these things usually aren't moody, I've made a turbo engine out of 3 engines in my parts pile and ran it for like 7 years and going...

 

[johnnyboy110]

So I have no idea if this has anything to do with it but it does have a cheap Amazon sub amp in it. The power wire runs right past the ecu. I don’t know if this could possibly F up the ecu signal some how. I’ll keep you posted.

 

[Mechrick]

t’s 3000rpm full throttle in any gear

If the ECM *thinks* it's in park or neutral it will limit RPM regardless of the shifter position.