My 1992 f150 302 is having some problems again. With the truck on at idle it starts smooth then the rpms drop comes back up where it should be then drops again. It will do this until it eventually dies altogether. It also cuts off while coming to a stop periodically, now after driving it tonight it wants to cut off while driving too.

I replaced the fuel pressure regulator and the map sensor. It still persists.

I'm thinking it might be a vaccum leak somewhere but I checked all the lines, they are fine. I'm gonna spray some carb cleaner around the intake gaskets tomorrow to see if maybe one of them are leaking. It did get real hot on me a little while back (electronic fans weren't working and I didn't realize it).

I honestly don't think it's one of the gaskets. They were all replaced a couple months ago.

Any ideas? Haven't pulled codes yet, don't have a reader and advance auto doesn't do obd1. It's gotta be something real stupid I'm missing, I just don't wanna start buying parts I don't need.

 

You need to check the codes. Just ground the STI wire, get behind the wheel with paper and pen. Then turn on the key and start counting the flashes of the MIL in your cluster.



OR

Buy one of these:


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Finally got my code reader and got the codes pulled.

I pulled codes:
45 - Thermactor Air Upstream
172 - HEGO (HO2S) Sensor Fault/ Lean
225 - Knock Sensor Fault During Dynamic Response Test
332 - Insufficient EGR Flow Detected
411 - Cannot Control RPM During KOER Low RPM Check
536 - Brake On/Off (BOO) Circuit not Activated During KOER
558 - EGR Valve regulator Solenoid Circuit Fault

Im assuming that one of the codes above is responsible for the truck running badly. Im thinkin replace the EGR, O2 Sensor, and Knock Sensor should take care of it and get it runnning right as rain again. What is code 45 though? Is that saying the smog pump is bad? I tried searching for it and couldnt find it, everything i found was on code 44 Thermactor air system fault.

I also pulled a bunch of transmission codes, which I expected. I recently replaced the E4OD with electronic shift BW1356 with a C6 tranny with manual shift BW1345. So I wanna wipe these codes and prevent them from coming back. I currently have all the plugs that went to the E4OD and BW1356 just zip tied up to the frame.

621 - Shift Solenoid #1 Circuit Fault
622 - Shift Solenoid #2 Circuit Fault
624 - Electronic Pressure Control Solenoid Circuit Fault
626 - Coast Clutch Solenoid Circuit Failure
629 - Converter Clutch Solenoid Circuit Fault or Lock-Up Solenoid Circuit Fault
632 - Overdrive Transmission Concel Switch/ no Action During Self Engine Run Test
636 - Transmission Oil Temperature Higher or Lower than Expected
637 - Transmission Oil Temperature Circuit above Maximum Voltage

 

You will not have a two number code if you have three number codes. You can not have both.

To do away with the transmission codes just replace the PCM Computer with one for a C6, AOD or standard transmission.

 

Yeah that's what I thought too, but it definitely came back on the reader.

I ran it twice because I thought it malfunctioned. Code 45 came back both times.

 

What kind of a reader do you have?

 

Same you showed in the picture

 

So I replaced the EGR and EVR today and it didnt really change anything. I read that there are two different kinds of EGR sensors that sit on top of the valve, a black and a gray and that there is a difference in the two. I have the black one so im gonna replace it with a gray one.

But I pulled the codes again and now I have some different ones. This is slightly frustrating haha

167 - Throttle position sensor fault during dynamic response test
334 - EGR closed valve voltage high (Im assuming that this is from the wrong sensor on top of the egr valve)


I still have some of the old codes being pulled too:


172 - HEGO (HO2S) Sensor Fault/ Lean
225 - Knock Sensor Fault During Dynamic Response Test
411 - Cannot Control RPM During KOER Low RPM Check
536 - Brake On/Off (BOO) Circuit not Activated During KOER

At least now the 2 digit code #45 is gone lol

 

The 167, 225 & the 536 were more than likely operator error.

 

what do you mean? How can there be operator error, All you do is plug the thing in and let it do its thing

 

During the KOER tests the operator (you) are supposed "goose" the throttle, step on the brake, and for trucks w/E4OD cycle the OD switch Off/On at certain points during the tests.

Hence the reason for some operator induced errors.


Innova 3145 User Manual

 

AHH ok yeah i did not do that.

 

I was reading your fault codes and recently fought similar problem pertaining to Lean and Cannot control idle codes.

Have you inspected the vacuum canisters on the passenger side wheel well and underneath the driver side washer/coolant reservoir? If you have the steel version of these, they rot out easily underneath and you can't see it. This will cause lean codes as will weak fuel psi. I had to replace both of my vacuum canisters on my '92 300 and it solved those problems.

 

No it's not the cans. The can that runs the cruise control isn't even being used. The cruise doesn't work. And the passenger side can is in good shape.

 

Just replaced the tps and it did not fix the problem either.