92 f150 bogging

[danmano2000]

Hey all!
I have an interesting problem with my 92 5.0 f150.
The truck fires up and runs great. I'll take it down the road, and it will continue to run great for a couple minutes, at which point it bogs down.
I push the clutch in, turn key off, turn back on, let clutch out again, then it will run great again for a few minutes.

I'm at my wits end on the one.
I have replaced both fuel pumps, I have good fuel pressure, replaced throttle body and MAP sensor. So far no difference.

Any help would be greatly appreciated.
Cheers!

 

[rusty ol ranger]

Get a vacuum gauge and use it to check for a plugged cat. I cant remember the exact way to do it but it would be a good place to start.

 

[19Walt93]

We had problems with fan clutches in the early 90's. The clutches would often lock and cause an extreme lack of power, customers would say they couldn't go over 50 and the truck sounded like an airplane. Do you hear a loud howling noise when the power drops?

 

[SenorNoob]

A couple minutes? Like the amount of time it takes the O2 sensor to become active?

 

[danmano2000]

Get a vacuum gauge and use it to check for a plugged cat. I cant remember the exact way to do it but it would be a good place to start.

Thanks for the advice.
I don't have a vacuum gauge, so I just opened the cats up and emptied them.
Neither of them were too bad, and it unfortunately made no difference.

 

[danmano2000]

We had problems with fan clutches in the early 90's. The clutches would often lock and cause an extreme lack of power, customers would say they couldn't go over 50 and the truck sounded like an airplane. Do you hear a loud howling noise when the power drops?

I will have to pay attention next time I run it, but I haven't noticed anything like that.

 

[danmano2000]

A couple minutes? Like the amount of time it takes the O2 sensor to become active?

Potentially... I never really thought of that.
I might have to take a look at that, thanks

 

[rusty ol ranger]

Potentially... I never really thought of that.
I might have to take a look at that, thanks

Is it throwing a check engine?

 

[danmano2000]

Is it throwing a check engine?

Probably, but I'm not sure. I had to remove my check engine light last year for a vehicle inspection. And it's also too old for obd 2.

 

[SenorNoob]

Testing EEC-IV Equipped Engines

OBD-I Diagnostic Trouble Code – 2-Digit Ford Codes

OBD-I Diagnostic Trouble Code – Ford 3-Digit Codes

Just gonna leave these here.

 

[danmano2000]

Testing EEC-IV Equipped Engines

OBD-I Diagnostic Trouble Code – 2-Digit Ford Codes

OBD-I Diagnostic Trouble Code – Ford 3-Digit Codes

Just gonna leave these here.

Thanks, come to think of it, I do have access to an old school obd-1 scanner

 

[rusty ol ranger]

Thanks, come to think of it, I do have access to an old school obd-1 scanner

Definantly scan it.

If you cant get a hold of that scanner look up the innova EEC IV scanner. I got one and its very simple and clear to pull codes with.

Last i looked it was like 35 bucks.

 

[danmano2000]

Definantly scan it.

If you cant get a hold of that scanner look up the innova EEC IV scanner. I got one and its very simple and clear to pull codes with.

Last i looked it was like 35 bucks.

My boss actually gave me the scanner, so I took it home yesterday. The only codes were "intake air temp sensor" and "coolant temp sensor." I replaced both, haven't had a chance to take it on a test drive yet, but just running it up to temperature, I think that might have fixed it.
I'll keep y'all posted

 

[19Walt93]

"sensor out of range" isn't a diagnosis, it's a symptom. I'd look for the reason those sensors are out of range. The scanner should display codes that will send you to the start of a diag path. Autozone uses a scanner that displays text so they can sell more unneeded sensors.

 

[danmano2000]

"sensor out of range" isn't a diagnosis, it's a symptom. I'd look for the reason those sensors are out of range. The scanner should display codes that will send you to the start of a diag path. Autozone uses a scanner that displays text so they can sell more unneeded sensors.

Thanks for the advice.
I cleared the codes, ran it through a few drive cycles and nothing came back.
Still runs like shit.
Ran a KOER self test, test came up with "can't control rpm at high rpm"
"Can't control rpm at low rpm"
I'm I'm going to replace the IAC, it is definitely sticky. That should be here next week