Bad idle in drive | Rev's in Neutral, stumbles in Drive

glockranger2010 · #1 11-22-2011, 05:04 PM

So, the short story is, my 4.0 4x4 2000 Ranger is doing some crazy stuff.

In Neutral/Park, I can step on the gas and it rev's as high as I dare.

I put it in Reverse or Drive, and step on the gas and it stumbles along at 200 rpms and dosent go anywhere.

It only has 102,000 miles (I got it at 95,000 and I've had it for 2 years now--hardly drive it--GT mustang is daily driver).

replaced the fuel filter, and fuel pump. I inspected all the vaccum hoses (and ran a vacuum test), has 65/70 psi fuel pressure.

I havent replaced them yet, but the O2 sensors (3 of 4) are flashing bad codes. I think that is the reason the check engine light is on, but why would it rev just fine in park or neutral, but in drive it would basically stall out?

The Cat seems to be working properly (no flow restrictions since exhaust can exit just fine in neutral/park)

Any thoughts?

pitbull · #2 12-16-2011, 01:03 PM

try pulling the 02 sensor before the cat out and drive if the power is back replace catyletic converter! good luck

GhostRanger · #3 12-16-2011, 01:47 PM

I gather that it is an automatic transmission as you say Park, Drive, etc. If your truck runs fine when not in gear then the exhaust is not your problem. Try and get the codes pulled and if you have an O2 sensor code look into it. But you may have a problem with the transmission. That is at least my .02 cents worth.

Also is your OD Off light flashing?

Boduke01Suder · #4 12-16-2011, 06:40 PM

Id look at your IAC valve. It can stumble your idle if it is bad. Mine had the same problem but in drive, I changed the IAC valve and it got rid of the stumble

tpwsr1 · #5 12-16-2011, 08:01 PM

Look at the IAC, MAF and the 0-2s.

glockranger2010 · #6 12-17-2011, 04:49 AM

We fixed it!....when we pulled the tank out to replace the fuel pump, going back in one of the gas tank straps pinched a wire harness, which tripped/blew a fuse relating to the O2 sensor.

runs like a champ now.