Long story short. My son came home to change his oil, said he had a rattle, initially thought it was a heat shield but couldnt find anything loose. Had a shop look at it and was told something was rattling inside the converter. Later, on his way to his place, driving on the interstate, cruise control set at 80, tapped the brake for slower traffic and wouldn't accelerate, would idle but quit when he gave it gas. He had it towed to a Ford dealership, a week later he called and they did a compression test, smoke test and replaced the plugs, (without asking first). Said it would run with the EGR pipe off. Wanted to drop te fuel tank and all kinds of fun stuff. I went and got the car, replaced the EGR valve and it will idle but won't take gas. Had a check engine light for barometric pressure and something else that I don't remember. After researching everything pointed to the converters clogged. Replaced the converters last night, fired it up and had an exhaust leak hissing where the Y pipe connected to the tailpipe but same issue, wont take gas and no check engine light. Took the EGR pipe off the EGR valve and it idles and takes gas.....Any suggestion greatly appreciated....

 

I'm a nooby having only recently purchased one, but I believe there is also a EGR sensor that sends data to the ECU. If the sensor is defective or has a wiring issue, the ECU might get confused. When that happens it fires up the auxiliary engine system......... the parts cannon llc.

Hope that helps. Just grabbing straws, but that's my only straw.

This is also my first post here, I'm pretty sure you will get better advice hear from others with more experience.

 

Any info at this point is appreciated!

 

I'm a big proponent in cause and effect analytics. Since you replaced the EGR valve, you might consider replacing the EGR sensor which monitors the physical position of the valve being open or closed. Because removing the hose allowed the ECU to allow fuel, there is something the ECU doesn't like and the signal comes from the EGR sensor. That doesn't mean the sensor is defective but certainly suspect. There could be an issue with the wires connected to it. I believe the sensor uses zero volts dc and 5 volts dc for feedback to the ECU. That would be a good place to start. The sensor is either mounted on top of the valve or close by. A vacuum leak in that circuit will also confuse the ECU.

 

Apparently the EGR sensor is on the EGR valve. I put a new one on it a few months ago, exchanged it for another one today in case the other one wasn't working correctly and same result. Now getting codes for EGR, barometric pressure, intake air temp high, manifold absolute pressure, mass or volume air flow A circuit and egr control circuit.... frustrating

 

I have a short suggestion and a long theory.
Disclaimer: I'm not a mechanic by any means.
A rattle turned into a nightmare subsequent to leaving a shop, whereupon the Steelership took further advantage.

First, do a KAM reset by disconnecting the negative battery cable for 30 minutes. That will clear all of the learned memory in the ECU relative to air fuel ratios and learned adaptations from driving habits. Clean Slate.

Use or borrow a OBDII code reader that has data stream function. Leave EGR hose off and start engine. The car will run "open loop" utilizing the preprogrammed fuel tables stored in the ECU until the cats warm up. Then it will go into "closed loop" using the O2 sensors to adjust air fuel ratios. Turn off car, plug the OBDII into the ecu port and scroll down to data stream, then pick MAF.

I suspect a faulty MAF Sensor, but they are expensive and I don't want to send you down an expensive rabbit hole.

The EGR hose just transfers a small portion of the exhaust gas to the intake manifold to help lower the temperature of the exhaust gas coming out of the exhaust port which lowers the temperature of the exhaust in the catalytic converter which lowers the nitrous oxygen contaminates that is the biggest air pollutant. With the data stream you can also look at the MAF data at idle, the short term fuel ratio, the long term fuel ratio, throttle position %, barometric pressure, intake air temperature, idle air control, lots of stuff.

Not sure your engine. I have a 5.0 and I have some video clips showing normal fuel trims and a MAF measurement at different rpm's. I can share if that would help.

Check data with scanner after KAM reset when things are working. Then check datastream after pulling hose when things don't work so well. Look for the gremlin. He's hiding. I wouldn't go back to the shop that analyzed the rattle.

For some reason, the ECU is telling the fuel injectors to not have any pulse width. You may want to check fuel pressure on the fuel rails.

The MAF Sensor measures the weight of air mass passing by it. It then sends data to ECU. ECU calculates the amount of fuel needed to meet stoichiometric ratio of 14.7:1 air/fuel. The EGR exhaust gas would not change that, it would only be sensed as a change in air fuel ratio by the O2 sensors.

I think the OBDII meter will becomes your best friend.

There are at least a have dozen sensors that send dsta to the ECU and they all have to work well together.

At the end of the day, this is a FUEL problem. The fuel injectors have to have a minimum amount of fuel pressure to operate (I think).

When you step on gas, the throttle position Sensor tells the ECU where it's at .........that could be problematic. When the throttle body opens, the manifold vacuum changes.

Lots of sensors.

I hope a mechanic chimes in.

 

Unplug electrical connector to EGR sensor. Leave hose connected. Do a KAM reset. Start engine. Engine does not even need the EGR system to run. Check for frayed or burned wires around the O2 sensors under the car. It sounds like a short somewhere. I don't think the EGR hose or the EGR or EGR sensor has anything to do with your problem. When OBDII is hooked up it will show position of throttle without engine running, just step on gas with key turned to accessory and engine off. That will verify the throttle position sensor is working or not. I just disconnected my MAF and it still ran. Sounded like it was gonna blow up, but it ran. Sounds like wiring issue or a short. Which makes it harder to fix. Hook up OBDII, it will help you figured out what is going on.

 

I will have to bow out, but before I do I will get you back to square 1.

After losing sleep trying to figure this out, I realized this morning that all the recent Cel's were from the EGR hose disconnected. At idle and WOT, the EGR valve is closed, the ECU dictates that and the sensor confirms it.

Removing the hose with the engine running changed the intake manifold vacuum and the bar pressure in the valve covers (my opinion). So I believe the barometric pressure, MAF, MAP, intake air, fuel ratios and something I've missed got the ECU upset and spit out a plethora of engine codes. Do a KAM reset after attaching hose and all electrical connectors. Then start car. Check codes. As long as it starts and idles, you can look at the fuel ratio in the datastream, Lambda values are less confusing. A decent OBDII meter is less than 100 bucks on Amazon. That's how I fix my pony.

If you can send me fresh codes or data stream info, I may be able to help, but as it is......it's too confusing to me and I get confused easily. 🤔

 

I think the best test would be to check the fuel pressure in the fuel rail. I think you can rent the tester at auto parts store or buy from Amazon and have the next day. The OBDII scanner won't measure it and the ECU doesn't monitor or control it. It only changes the electrical pulse width of the signal to the fuel injectors. Wider pulse means the injectors stay open longer and release more fuel. Seems like you have spark and oxygen, fuel would be good. Funny how the Ford dealer wanted to drop the fuel tank. I think the fuel pump is just drop in. Verify the battery is good and the altenator charges at least 13.9 volts minimum. Many a problem is for low voltage and the ECU does not like low voltage. I think the fuel pump is voltage sensitive in that it pumps a tad bit more with a slight increases in voltage. There is a regulator or bypass valve or feed back line for excess pressure but nothing for insufficient pressure. When you turn the key to accessory, you can hear the pump pressurize the fuel lines, then stop when pressure is correct.

Just more things to consider. I don't know why Ford couldn't fix it.....its not rocket science. The auto shop and dealer just want your money. I would rather get Covid than visit either. 😷

 

Make SURE your cats aren’t plugged! They will do strange things if they are. I had a thunderbird that would run if you took a spark plug out , wouldn’t start otherwise! Cats were melted.