Rough Idling..
 

Hi guys, I have a 1999 2.5 gasoline ranger. I bought it a short time ago, the idle has always been a little inconsistent, but lately it has become more noticeable, to the point that after accelerating hard and braking quickly, the engine shuts off.
I disassembled the injection body to clean, cleaned the injectors, changed the IAC and TPS, both MTE Thomson. I changed all spark plugs, air filter, checked fuel pressure (60Psi). MAF sensor is reading 3.1-3.9.
I haven't been able to do a cylinder compression test yet, but it has no problem in cold starting.
I'm starting to think it could be a false air intake, or a bad head.
If anyone can give me some advice, I'd appreciate it.
sorry for any spelling mistakes, bad english

Always start with a compression test or you will end up chasing your tail.

Hi gabriel9102,
As RonD will most likely explain (He's like the resident Ranger Guru) Ford used a "solenoid" type IAC valve for these engines. Most brands are the "stepper" type valves and don't work properly, and can cause all types of issues.
New Motorcraft IACs are hard to find but Hitachi is the only other brand (so far) that sells the proper replacement IAC valve.
Here is a link to the one I put on my 2000 Ford Ranger;


Hitachi ABV0016 Idle Air Control Valve

Of course you could have other issues such as a vacuum leak but with a stepper type IAC installed, that would be at least part of the problem.

Here's a link to a thread of mine with more info from RonD, I had pretty much the same questions as you.
https://www.ranger-forums.com/sohc-2...1/#post2203537