Questions and Answers

Ford Ranger Bouncing Idle Q. I just bought a 1997 Ford Ranger 4.0 automatic transmission with 43,000 miles on it. When test driving the vehicle, I noticed that the check engine light was on. This didn't really bother me but I still brought it up when we were negotiating the price. We reached an agreement that they would fix any problem that was causing the light to come on. So they "fixed it" and I drove it home and it came right back on.

Then I noticed when I come to a complete stop, the car would act like it was going to die. RPM's would go from 1,000 to 700 back and forth, back and forth, until finally I heard a click, and the RPM's would jump to about 1300 and it would be fine. A couple days later, the problem continued, but sometimes, it would actually die when this happened.

So I brought it in, and they said it was the MAF sensor and they replaced it. After that, I drove it home and the check engine light was off. The next day, it came back on. And I still noticed (though not as bad) the problem with the idle when I came to a complete stop.

So I brought it in yet again, and this time they claim it was the EGR valve. SO they replaced it, and I drive it home and not five minutes into the drive, the check engine light comes right back on, and the problem with the idle at stops is still there. I talked to my mechanic, and he said that Rangers are known for some problem with an Idle Air Control Valve.

Do you believe this is what is causing the bad idle and the light to come on? Did I just get a lemon of a truck? Please help. I will print your e-mail and bring it to the dealer because they seem like they don't know what they are doing. Because, three tries, and still the problem continues.

Thanks much...

A. If they are getting Diagnostic Trouble Codes (DTC's) P0171, P0174, P1131, and/or P1151 then I would look at the gasket between the fuel rail and lower intake manifold. The 4.0 had a habit of sucking these gaskets in and having them for dinner. If that is the case, there is a new manifold gasket for replacement. The P/N is F8PZ-9E436-AA.