I own a 1986 Ford Ranger 2.9L V6 and A4LD auto trans that has been running rough and intermittently missing for the past almost 2 years now. I’ve talked to tons of other people who told me several different sensors/modules could be acting up. Replaced a bunch of modules and checked a bunch of module…

I’m assuming you mean the vacuum solenoid when you say the control port. There’s two vacuum lines coming out of the solenoid, one goes to the EGR valve and the other goes to the intake manifold plenum, there’s also a line going from the EGR to the EGR pressure feedback sensor. Which would I measure …

@kxri318 Did I miss that part where you replaced the EGR feedback sensor? You mentioned all of the other EGR components. If not, replacing the feedback sensor should be your first step. A faulty feedback sensor will set an EGR code and cause the engine to run rough at idle, miss, and run rich.

Yeah, I replaced the pressure feedback sensor and saw no change in how it ran.

I still wonder if the problem may be coolant leaking into one of the cylinders from a defective head gasket or a cracked cylinder head as a I suggested in an earlier post. I would suggest letting the truck sit overnight or longer and before starting the engine, remove the spark plugs one at a time …

[image] kxri318: There’s two vacuum lines coming out of the solenoid, one goes to the EGR valve and the other goes to the intake manifold plenum, there’s also a line going from the EGR to the EGR pressure feedback sensor. Which would I measure at? I’m not familiar with the EGR system configur…

fyi, a discussion on the early 90’s Corolla’s EGR configuration for comparison. It seems like it is pretty similar to Ford’s method used on your Ranger [image] Corolla EGR System Maintenance/Repairs Just trying to understand how the egr vacuum switching valve works. 4…

I’m pretty sure I would measure it at the line going from the solenoid to the EGR valve. Also, I noticed whenever I turn on the headlights that my RPM drops about 50 or so, its a difference I can hear, is that normal? I’ve seen conflicting things like that’s normal because the alternator has to work…

[image] kxri318: I noticed whenever I turn on the headlights that my RPM drops about 50 or so, its a difference I can hear, is that normal? My Corolla’s idle rpm increases 50-100 rpm (by design) when I turn the headlights on. Whether than applies to an 86 Ranger, don’t know. It doesn’t hap…

Perhaps a smoke test for a hidden vacuum leak.

I’ll try that. Probably will rent a vacuum pump from autozone to read how much vacuum the system is under too

Weird Electrical Issues Seemingly Unfixable

Maintenance/Repairs

George_San_Jose1 September 21, 2023, 10:19pm 35

fyi, a discussion on the early 90’s Corolla’s EGR configuration for comparison. It seems like it is pretty similar to Ford’s method used on your Ranger

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