I have a 1997 Ford Ranger XLT 4.0 V6 automatic transmission 184000 miles 4x4. And I've fixed things on it but there is one issue that has been a massive issue for a while now that started in 2022 and we have not been able to figure it out. When coming to a stop at a stop light or sign, being stopped in drive say at a restaurant drive thru, or when tapping the gas pedal the RPM will jump down below the normal 900 - 1000 RPM idle to around 500 and jump back up, do the same thing as the previous point but multiple times in succession when going slow or stopped accompanied by a low rumble and a lurch feeling when it happens and more of a vibration, or it just straight up cuts off. When it cuts off its like when a manual vehicle stalls, the only thing that cut off is the engine everything else is still on and then I'd restart the vehicle and keep trucking. I havent noticed anything at higher RPMs and have had multiple parts replaced to no avail such as the fuel pump, fuel filter, transmition fluid and a solenoid when we took it to a transmition shop 2 months ago, alternator, and IAC replaced with a genuine motorcraft part. I haven't done the coil pack/spark plugs but the engine doesn't seem to be misfiring though I do plan on possibly replacing them as a preventative maintenance step. So what does everyone think I was thinking torque converter but at this point I have no idea.
Thanks, Evan
Does it still do that when the truck is in neutral? Putting the truck in neutral takes the torque converter out of the equation. If it still does that when the truck is in neutral, it's not the torque converter.
Sounds to me like a vacuum leak. When was the last time you changed your vacuum hoses? If they're still the original hoses, they're dry-rotted. I had this happen on my '79 Pontiac Catalina. It had vacuum leaks galore when I first bought it four years ago. The car would almost stall when you touched the throttle, then it would "catch up" and the motor would start acting in accordance with the throttle input. Once I had every vacuum hose right, it cleared right up.
@justin-shepherd I have replaced a couple of vacuum lines but not all of them. So yes most of the lines are original. I need to try putting the vehicle in neutral to see what happens
@justin-shepherd I tried it in neutral and it still did it. Is there any way to figure out where all of the vacuum lines are?
Is there any way to figure out where all of the vacuum lines are?
If there is no vacuum diagram under the hood that information should be in the repair manual.
