Let me start out by saying thanms for having me at this forum. Ok i have a 1997 e350 work horse with the 6.8. This is my first ford so i do not know a whe lot about them. I purchased this at a reasonable price because it ran like crap. I pulled codes it had 4 plugs missing and lean bank 1 and 2. I put all new plugs in. With boots. Did tests on all cop and they all tested good.also i replaced the egr computer part. That was also a code it pulled. Cleared codes and it runs but not well has a major hesitation and smells like a gas factory out the tail pipe. Running way rich. And is not as responsive as it should be. No codes are present now. Please help. I love this van!

 

I'm not an expert but sounds more like injector issues than spark/timing to me.

But then, I'm not an expert!

 

Did you clean the MAF?
Check the IAC valve and the TPS sensor.
Check for vacuum leaks, particularly the PCV line.

 

Yes i cleaned the maf sensor and i have not cleaned the iac or tps. Eouldnt they throw codes?

 

Also as i come up to a stop sign she acts like she wants to quit

 

The IAC valve may be gunked up.
The TPS may not be smoothly changing throwing off the PCM.
They may not set codes.
Both are not that expensive, change one at a time.
Did you check all the vacuum lines?

 

Clogged cat?

O2 sensors?

 

I am going to change the vaccum lines they are bad looking but couldnt really find a definate vaccum leak i did however notice the dpfe vaccum hose is actually pushing air not a vaccum thos may be a problem. I am going to test the tps and iac like you said. Not sure about the cat conv. I do appreciate the help thanks

 

It's interesting that it had lean codes, but it sounds like you did nothing to fix a lean condition.

Check for vacuum leaks - one thing that can make it run rich is the fuel pressure regulator not getting vacuum which makes it set the pressure to 38-40 psi which is too high for idle.

At idle, the fuel pressure regulator should get full manifold vacuum. Check there first. I'd also check the fuel pressure at idle, it should be 28-30 lbs.

 

Clogged cats will first start affecting high speed or heavy load conditions, not allowing the engine to get up to full power. The max speed starts to drop. For example, a hill you used to be able to go up at 70 mph now it will only do 60 mph, then 55 mph, etc. Eventually it will only be able to do 35 mph on level ground. A cat with a broken up ceramic will get you to the 35 mph limit right away. The engine will rev and idle fine, but have a massive loss of power. During the early stages you can even get up to 65 mph if you do it slowly, but there will be noticeable loss of power when accelerating hard. There are exhaust pressure testers available (ebay $30) that plug into an O2 port.

 

Someone disconnected o2 sensors and i am not getting alot of exhaust out the tail pipe maybe cat is clogged

 

i changed pcv valve, tps, cleaned iac, disconnected exhaust at cat conv. Now when i start it runs good for about 2 min then starts missing intermitently then constant. Wondering if injector bad? Or is a coil shorting? Still no codes when i scan it.??????

 

So it runs fine when it's cold and crappy after it warms up.
Two things I can think of that change when the engine gets hot.
First, the engine coolant temp sensor for the PCM will show a higher temp.
But, if the sensor is bad and the PCM reads an incorrect temp when the engine is hot that is probably an issue.
Try finding out what temp the PCM sees when the engine is hot.
The 2nd is the PCM switches from open loop to closed loop control.
Not exactly sure what that is, yet.
It involves the O2 sensors and cats.
I think the O2 sensors have heaters to get the change over to happen quicker.
There are articles I've seen with Google searches discussing it.

 

Are the O2 sensors hooked up and functional?

 

yes o2 sensors are hooked up i have the exhaust disconnected at y pipe and cat. So i can hear the motor better the miss seems like one cylinder to me. And i am getting no codes. That is why i thought maybe a coil break down. It also still has a hesitation at acceleration. I umderstand about coolant temp sensor but would that throw a code? Suprised about no codes. When i got the van it would barely pull itself its alot better just hate the miss.