Need help with my sons car

[toomanytoys]

Scanner is a actron cp9580 and yes it works. I forgot to plug in my maf after I cleaned it and got a code. Also got a code when the dpfe broke. Plugs are new don’t remember the brand. It’s pouring out so I hope to get to look at it tomorrow after work

 

[awful knawful]

Egr

 

[toomanytoys]

Egr how? I was reading that some ports can become clogged forcing all the gases to one or two cylinders causing the misfire. Is this what you’re referring to? This car is driving me nuts. Now I have a cel for “o2 sensor high voltage “ on the bank 2 downstream sensor. Yet on the scanner it looks like it’s not switching and is stuck at .040.

 

[hotcobra03]

Egr how? I was reading that some ports can become clogged forcing all the gases to one or two cylinders causing the misfire. Is this what you’re referring to? This car is driving me nuts. Now I have a cel for “o2 sensor high voltage “ on the bank 2 downstream sensor. Yet on the scanner it looks like it’s not switching and is stuck at .040.

Did you find key on engine running test in special features

This scanner may not be enough

Cp9680 plus was more like my Bosch 1350
Has many ford on demand tests

Is this a borrowed tool or yours

 

[toomanytoys]

It’s mine

 

[Crimson2v]

Egr how? I was reading that some ports can become clogged forcing all the gases to one or two cylinders causing the misfire. Is this what you’re referring to? This car is driving me nuts. Now I have a cel for “o2 sensor high voltage “ on the bank 2 downstream sensor. Yet on the scanner it looks like it’s not switching and is stuck at .040.

The EGR ports on the 4.2 would clog up and allow burnt exhaust gasses to enter the cylinders and cause misfires. You can test this by applying vacuum to the egr valve and the engine should cut off if it’s working properly. To me it sounds like you are dealing with partially clogged cats. If your exhaust is clogged it will back feed into the engine causing random misfires. It’s tough diagnosing over the internet, we are trying to help out the best we can.

 

[kevinatfms]

I’ll get that reading later. Would explain the melted emissions hose and dpfe right?

If its the original metal DPFE they were prone to shorting internally and even then wouldnt set a code. There was a TSB/Recall on them to replace the metal and early plastic version to the updated part number.

There might have been a recall on them. I cant remember specifically(its been 10+ years) but something about them maybe catching fire or melting the wiring harness below them causing catastrophic failure while driving. Or it could have been a TSB. My mind hazy after a few years of not having to deal with them.

 

[Tifosi2003GT]

This and these cars are only know for valve seat's dropping so leak down test is important

2. Intake gaskets. I know you said you replaced them but alot of times guys pinch them when putting the intake back on. Id double check using carb cleaner and see if the STFT changes when you spray around the intake base

 

[hotcobra03]

Tsb for iac from link

https://www.chiltonlibrary.com/lh/TSB/ViewTSB?assetId=34632

 

[toomanytoys]

The stft is already on the negative side pulling fuel. It’s the long term that’s adding but still well within the parameters at +10.8-11.2

The only recall I had done on this car was the air filter. Something about fibers getting into the maf and burning

 

[vortecd]

You could have one or more fuel injectors that are bad. A Mustang I had did and it didn't show any codes

 

[toomanytoys]

I was wondering that too. Guess I need to temp probe the manifold while the engine is running and look for cold spots

 

[hotcobra03]

Dumb question.

What about motor mounts.

You say it’s when you nail it it falls.

Would a bang on mount be enough to trigger knock sensor?

 

[hotcobra03]

Or a hole in tube from air box to throttlebody.

I had a friends Mazda. Idle great. Put in gear motor would tilt and air would get in after maf. No code but miss fire and spuder

 

[toomanytoys]

All good ideas. I’m going to be looking over this car on Saturday and hope to find something

 

[toomanytoys]

Update : I ran some tests on my sons car today and here are some of my findings—
The car is holding 20 inches of vacuum at idle rock steady and it drops when the engine is revved
There are absolutely no vacuum leaks at the upper or lower manifolds as well as the pcv or around the TB
The egr stalls the motor when vacuum is applied to it at idle
Fuel pressure is between 37-42 psi during these tests
When the car misses and pops it’s on random cylinders
I changed the downstream o2 sensor on bank 2 as it had stopped switching and I put in a new fuel filter and cleaned the maf

All this and there is no change

 

[Crimson2v]

The vacuum drops when you have it revved to 3k, not a quick throttle snap? I am really leaning to clogged exhaust if that is happening. You can pull the front O2 out and check the backpressure reading. Was the rear O2 switching before? If so it’s not supposed to, if the rear is switching that is a sign the car is done.

 

[toomanytoys]

The rear o2 sensor was stuck at 0.045 volts. And I got a code of failure to switch. There was no movement like the other three. I can rev the car to the moon if it’s smooth and deliberate acceleration. A throttle snap causes a bad stumble and even detonation sometimes. What controls injector pulse? Is there a cam sensor?

 

[Crimson2v]

.45 volts is indicating lean, normal operating temp the rear O2s should stay steady at around .7v. The CKP controls injector pulse and there is a cam position sensor. What where the codes when you started diagnosing this issue?

 

[Crimson2v]

Also what fuel are you using for the car? Is it a flex fuel car?