I'm over trying to explain it to my dad, he bitches at me everytime I talk about repairing anything anymore, no I don't live with him, but at times I make the mistake of asking him to help fix something. He was going to change the fuel filter but since the removal tool didn't slide in easy he quit, figures it don't need it anyway, yet it's a cheap item that you can do yourself, it could be the cause.
It's not the MAF, or PCV, in fact he talked to a mechanic who suggest stop just replacing things, so his take on it is to drive it until it quits. I don't see driving it with a miss as being good for it, and when it is torn up I will get lectured on that as he paid for the transmission. It ran fine till the transmission swap, came back with that light on and a miss, yet all I've gotten is the transmission shop says it ain't on their end. I reset the codes and it immediately came back before it got 5 miles put back on it, so there is an issue somewhere.
What I want to know is, what kind of damage can I look for just driving it anyway?

 

the most likely possibilities include vacuum leaks, disconnected vacuum lines, missing oil cap or other item allowing excessive air into the system, etc.
generally, if the fuel filter is clogging up, it'll starve for fuel in a way that you'll know about, stalling your engine or nearly so.

other possibilities include exhaust leak (air gets in and lies to the o2 sensor), o2 sensor that is wearing out and giving inaccurate readings but not bad enough to throw a code, dirty fuel injectors, etc. also, misfires can trigger lean codes, as the unburned fuel/air mix shows up on the sensor as o2 in the system.

as for possible damage, lean mixtures tend to burn hotter, which in extreme cases can cause various damage to the engine, but i suspect the computer will back things off and not allow it to get that extreme.

 

Being lean on both banks, odds of it being an injector, exhaust leak, and o2 sensor, no way. All my vents are working, even the rear AC, a leak would cause them to go to default, the miss is bothering me tho.

 

I ran it hard last night, I didn't feel a miss, I may wipe the codes and see where I am after it, I can't see how there is an issue, but as I said, before the transmission was pulled and replaced with a different one, there was no issues.

 

Mine was the mass airflow sensor when I got those codes all the time.

 

I've cleaned it already, it's a pain, I need to buy anew hosing cover, it's cracked, making it difficult to get back on, has nothing to do with the filter tho. I don't think the MAF could be bad without throwing a different code could it? If I could afford it, I'd get one from a Lightening, since I could use it to go with the rest of my upgrades.

 

I had the same codes and very rough running a few months ago. Turns out one of the band clamps was loose on the air intake, between the throttle body and air filter housing. While I was in there, I attempted to replace that little rubber elbow at the base of the throttle body...it is for the pass. side PCV valve/tubing. What a PITA!!! I ended up just putting some generic heater hose in place of the elbow. That will have to do for a few years.

 

I bought a GM hose, it had 2 90 degree bends, cut in the center, the result was 2 ends, so I have a spare, my intake isn't easy to assemble, it pops apart, the straight section at the rubber elbow doesn't like to stay together while installing it, I might wind up replacing it with a generic straight section.
I'm beginning to wonder if the miss was the gas, this E-5 doesn't last long before making varnish in the tank, I had it ruin 3 fuel filters, a fuel pump, and make my 73 require a carburetor rebuild, the stuff looked like molasses.

 

The problem I faced (with the PCV tube) was I could not get it over the nipple at the base of the throttle body. There is just no room to manipulate the hose/tube, even with special pliers. Of course, this is on the 6.8L. I think the 5.4L has it on the side or back. My 32valve 5.4L has it right on top, but it is larger than any generic HELP!-brand PCV tube/elbow.

Remi
01 E-350 15-pass 20valve
99 Expy4x4EB 32valve

 

My 5.4 has it at the back of the intake manifold, the plastic tubing pushes into a large rubber grommet, very easy, The stupid Help item was pretty useless, it's shorter than the factory elbow.

 

We just got back from an 8,000 mile, one-month cross country trip in our 98 E250 campervan. We got the check engine light somewhere in New Mexico. I had a code reader with me and saw that it was throwing the 171 and 174 codes indicating lean on both sides. I took it to a Firestone repair center (local dealer was booked a week ahead and I had little choice). The shop said it was sucking air through the intake gasket, and they replaced both sides. Two days later, and well down the road, the light came back on with the same codes. Since the fix was supposedly warranteed for a year, I took it to another Firestone that spent well over three hours running diagnostics on it (no charge). I was actually pretty impressed by the techs there; they seemed to be on the ball.

We replaced the MAF sensor, which was clogged. Also changed out the fuel filter (I had an extra with me in the van) for good measure, as I'm the second owner and didn't know when it was last changed. The light still remained on. Diagnostics showed that fuel pressure was somewhat low, but still within specs. Possibly a failing fuel pump somewhere down the road? They didn't charge me for the diagnostic time, didn't charge me to install the MAF sensor or my fuel filter, and were generally very helpful. Props to the Bernalillo, NM, Firestone! Nice guys. Not so much to the Santa Fe, NM, Firestone, which did a $500 repair (intake gaskets) that didn't solve the problem.

I'm not too upset about the things that were replaced, as the van is 13 years old with 80,000 miles, and I figure they were maintenance items anyway. But, I want to figure out what the problem is!

Anyway, we drove another 5,000 miles and made it home fine despite the light still being on. Now that I'm home I need to figure out what it is. Could it be that the computer just needs to be reflashed?

Grrrr....

 

I poured in 2 bottles of Techron, I'm sure it needs to go to the shop but I'm tired of fooling with it, these issues will nickle and dime you to death, had it not gotten the transmission replaced, I was to a point I could walk away, now I'm forced to keep it. Right now I plan 5to drive it till it quits, at the moment, the miss is gone, I reset the codes, I have to replace the fuel filter, dad couldn't get it easy, so he quit, just something I have to do myself.
It's not the intake, could be a vacuum leak, the damn canister I believe has started to bleed off, so when I have help, I'll be re-plumbing the lines up there.

 

The evaporative emissions system on my E-350 is leaking vapors, I suspect. The hoses are crumbling. I have replaced some of them, but not all. The rubber tubing is very, very similar to the same rubber tube on the vacuum canister for the HVAC system.

 

What makes you insist it isnt the intake?

Also, you mentioned the MAF housing was cracked, possible vacuum leak there? use a propane plumbers torch, not lit, to spray some propane toward the crack while running. see if it starts to race the engine. you can check each intake fitting as well.

 

The filter box is cracked, don't matter, comes from the factory with a big hole in the bottom, I guess for is water was to get in, no different than running an open element filter. The gas/ethanol could be bad, after filling it, the miss disappeared, my AC is dropping to default on occasion, could be the vacuum leak, but it's been that way for years. My intake is aluminum, not plastic, they are not known for leaks, I am bothered that it started immediately after returning from the transmission shop.