1997 F150 4.2L V6 manual trans

The main purpose for this thread is to figure out what these hoses hanging out of my passenger front tire wheel well are (pictured below), and whether there is anything wrong with them. Could this be a vacuum leak or causing any problems.



Hello all. My truck is running very poorly. It mainly runs very roughly at start, sputtering, shaking, cutting off, specifically in 1st and 2nd gear after being cranked for the first time of the day or after sitting a long while. It seems to go away mostly after the truck has warmed up. Getting up to speed, it hesitates going into gears, and then, after a pause, it finally lunges forward, as if something were blocking the fuel and then cleared away. Once it's up to highway speed, it's as if all were forgiven. It doesn't have any issues keeping speed and seems to shift within the upper gears without much issue.

I've been on the hunt for vacuum leaks. I did find a major one. What I think is an evap hose coming out from under what looks like a little black plastic cup with a twist off round cap right in front of the brake booster and feeding into the aluminum intake immediately after the throttle body. The hose had deteriorated almost in half. I just switched the hose with some rubber that Advanced Auto sold me. It certainly ran slightly smoother and stopped cutting off as often, but it's still got issues.

I was filling up the air in my passenger side front tire when I noticed these hoses hanging down from behind the wheel well cover. Some time back, I remember hearing a hissing noise near that front passenger fender. I went on and forgot about it, and over time, it seems to have stopped. As I look inside the holes, it looks like something has plugged them up. Some kind of bug nesting maybe? Anyway, I sort of squeezed the end a little, and a lot of debri fell out. There is still some in there. I pulled the hoses down so I could take some pictures. I've tucked them back up inside since. What are these? Should they just terminate like that? Is it possible that a hose or hoses have come out of the end/s? I tried to look and feel up inside the fender for other pieces that may have disconnected and are just laying there, but so far, I haven't found anything else.

I should mention that I changed the fuel filter, but there was no noticeable change. I wanted to replace the fuel injectors, but I'm not sure how to remove them. It looks like the aluminum upper intake must first be removed, unless there's some kind of alternative. I may go ahead and do it, but wanted to make sure it must be removed first before needlessly going through the trouble.

This truck is on it's third engine. The last one was a Jasper rebuilt. The odometer reads 319,000 miles. Other than the rough running, it starts up and keeps going. It's not my daily runner. I have another truck and car. I mainly use this occasionally for work or to move mulch or if I don't wanna mess up my other vehicles doing something dirty. It never carries heavy loads or hauls anything.

Thanks to anyone who cares to share experience and opinions.

 

Has it ever run correctly for you? Not clear how long you've had it.

Not clear what you mean by hesitating going in to gears, since it's a manual transmission. Is the clutch slipping or is the engine hesitating?

"My truck is running very poorly. It mainly runs very roughly at start, sputtering, shaking, cutting off, specifically in 1st and 2nd gear after being cranked for the first time of the day or after sitting a long while. It seems to go away mostly after the truck has warmed up. Getting up to speed, it hesitates going into gears, and then, after a pause, it finally lunges forward, as if something were blocking the fuel and then cleared away. Once it's up to highway speed, it's as if all were forgiven. It doesn't have any issues keeping speed and seems to shift within the upper gears without much issue."

 

I've had this truck for probably 20 years or more. It did use to run better, but has been doing this for a few years now. It seems the engine is hesitating, not the transmission. I was thinking more along the lines of something with the fuel system, intake or vacuum leaks or a combo of all the above.

 

Have you considered the basics, like a tune-up? Spark plugs. They're easy on the 4.2. Maybe pull one and take a look.

The IACV should be bringing your idle speed up to the level it needs to be to run smoothly when cold. I think that it also affects RPM drop when the throttle is reduced, like when shifting gears. Might be worth a look. They can get gummed up.

If you don't have lean codes then you probably don't need new injectors. The PCM will tell you if you have a fueling problem. Is the CEL/SES check engine light on?

Here's what the IACV looks like. It's on top of the throttle body on the front of the engine. Can't miss it. Might not be the main problem but it's worth examining. Easy to get to. You can also check it electrically.

https://www.rockauto.com/en/catalog/...ac)+valve,6072

 

Ok, thanks, I forgot to say that I had already cleaned out the iac and throttle body. I pulled a spark plug. It is a motorcraft brand, platinum. I don't know how old it is, a number of years tho. It's all sooty, but the shape seems to be intact. I've seen pictures of ones that were deteriorated badly. Can I just clean it? Of course this is only one out of 6. The others look to be a little more difficult to get at. This one is the driver's side closest to the firewall.

 

Looks dirty and the gap looks big. Hard to say. Is it burning oil?

You could clean them and regap them and see if you get an improvement. The fact that it runs well on the highway is a sign that nothing terrible is probably going on.

You didn't answer about the check engine light. It's a 97 so you have a lot of diagnostic power available just from the PCM. If you're decent with technology you can get a cheap code reader/scanner and watch live data while it's running. Live data, cold engine and warm, will tell you a lot without removing or replacing any parts all. Just plug in to the DLC/OBD port.

 

I don't believe it's losing oil. Two or three years ago, the Jasper rebuilt engine was leaking. I think it was the rear-main, which was replaced. If it is burning oil, it can't be much. The truck gets so little use, I don't change oil often. When I checked it last, it was black. I've read a few places that black oil isn't necessarily bad. But, I think I'll change it in the morning anyway. I'm going to try to drive it a few times so it gets some use.

I don't have a check engine light, which makes me wonder if it's working. I actually just received an XTOOL D7 bi-directional scan tool ( ), but I don't know what to do with it lol. It took me forever just to figure out how to get my truck to show up in it. The auto-scan didn't work with my truck. I had to enter the vin. Once that was entered, there is a lot of stuff available,so much I got tired of looking at all of it. I pulled some historical codes and here are a few of them:

P0113: (Air Intake Temperature Sensor, which I think is dead, and I can't get a reading from the harness either, but I think my leads may be to fat to fit in the tiny holes. I'm not sure I did it right, but the sensor wouldn't give a continuity reading. I just put it on ohms and touched the two prongs inside the sensor, nothing. The sensor also looks a little bent).
P1537: intake manifold runner control valves are stuck open
P1538: intake manifold runner control valves are stuck open
P1000
Iac 1 54%
Iac2 .535 A
Battery voltage 14.3
Exhaust gas recirculation system of pressure transducer .951 V
P0141 circuit malfunction of heater
P1131 switch lack, sensor indicates lean
P1151 "
P1408 EGR flow is out of self test

Thanks for reading, don't miss diner over my truck. I'm not in a hurry, and the trucks not going anywhere.

 

The P1537/8 is probably from the IMRC bushings falling out. I think 97-98 model IMRC is vacuum controlled for each bank, but they still use rods to move the butterflies.

I’m not sure you can access them behind the engine very well with those aluminum intakes, so that may have to be pulled. Fix that and the P1131/1151 should leave.

 

I think that just might be a vacuum leak…

 

Some of those could be the vacuum hoses to the DPFE sensor which is involved in EGR control. Might explain the EGR code. If the IMRC is vacuum controlled (mine is electric) that might explain the stuck IMRC code.

All of the vacuum hoses have a purpose. So any hose that's disconnected would be a problem. I'd drag them back up in the engine bay and see what they reach. Maybe you'll get lucky and it will be obvious. If not, find the IMRC and DPFE devices and see if they have a common connection point. Your first assumption might be the right one. Good luck.