'87.5 F-150 4.9

Having issues with acceleration and check engine light will flash only briefly during acceleration but not while in neutral. Checked the codes after the light came on (left engine running after the light AND tried to retireve code after the engine had been shut down but no codes stored).

New: Cap/rotor/wires/plugs (x2 in the last 2 years), egr, ignition coil, ECM, idle control valve, temp sensor, water pump, heater core, fuel filter, throttle position sensor, timing adjusted, fuel pressure regulator, cleaned throttle body, new O2 sensor, new steering gear box.

Mechanic ran fuel injector cleaner through (seafoam) and did a steam cleaning. I have done the FI cleaner through the gas tank as well but still have the same problem...

When accelerating it feels like there's a 'tick' .. some kinda glitch that is keeping this thing from running properly. Also, sounds like there's a vacuum leak - possibly a valve of some sort sticking open when it should be closed. The vacuum leak sound is coming from the backside of the engine near the firewall. The truck is getting pretty good gas mileage. I have had this truck to 5 different mechanics now and none of them have solved my problem.

Could it be an electrical issue or am I missing something here?

 

electrical issue...prolly a bad ground(s) and or shorted out ECM due to bad grounds...

 

Ok.. so where do I begin to have this issue resolved? Is there somewhere that specializes in this type of problem solving?

P.S. Just replaced the ECM

 

No codes at all? Not even 11?

 

Not ONE SINGLE CODE stored. I'm at a loss here...

 

And you changed the ECM.

I see you said '87 and a half which is interesting. I haven't seen any '87s wired for the check engine light, mine wasn't wired for it didn't have it. I did wire it in though. Are you checking for codes with a voltmeter or trying to use the check engine light?

 

The last mechanic I had do work on it hooked up the diagnostic code puller to it. We thought maybe when I turned the ignition off that it wasn't storing codes, but then the check engine light flashed briefly again the next day while driving and I took it directly to him and left it running so he could check it with the engine still running after the check engine light flashed. Still no codes.

Technically, it's an '87.5, but on the title it says '88.

 

It's an '88. Stop confusing me.

Screw that diagnostic machine, try it the old fashioned way. https://www.f150forum.com/f10/how-re...es-obdi-10907/

 

Thanks for the tip on doing it the old fashioned way. Here's what I came up with..

KOEO:
32
67 (not sure if it was 671?)
(and then it repeated (32, 67, but there was like a 6 second delay and then..)
1
32
51
63
32
51
63

There seemed to be a lot of repeat codes..

With the engine running, the self-test indicated code 32 twice and that was it.

How cooked is my goose?

Thanks in advance.

 

They all repeat them, its on purpose.