Folks,
My 98 RAM 1500 4x4, 5.9Lwas going down the road and suddenly lost power. It want pull itself up a small hill. It starts and idles fine. When you step hard on the peddle, it moans alot but doesn't go anywhere. Want go above 1500 rpm's even sitting in park and sounds like its sucking tons of air when you try to make it go.
I Replaced the coil, no difference.
I Replaced the TPS, no difference.
I Removed the O2 sensor from the CAT, no difference.
I can spray fuel into the throttle body, no difference.
The fuel pump assy is two weeks old and I have 48psi at the fuel rail while at idle and stays constant as its reved up.
Generates no fault codes.
Runs fine at idle and revs up to about 1500 rpm's before it starts choaking down.

Please HELP!

Thanks, Mark

 

check out the converter it is pluged up most likely . look at it and see if it is glowing red .

 

most likely a clogged up catalytic converter. to prove it you can temporarily remove the pre-cat o2 sensor to relieve some back pressure. if it revs up and runs a little better that proves its the cat.

 

Thanks, would it plug up all of a sudden like while going down the road?

 

The CAT is not red at all. I just let it run a while in the dark and nothing. Any more thoughts?

 

The honeycomb most likely finally brokeloose and got cockeyed in there.Instant plug, instant problem. If you don't want to upgrade to a high flow, the cats were recalled a while ago I believe. Don't know if you'd still qualify.

 

My 98 did the same thing quite a few years back. Just installed another last month.

 

Hi kayakman
When you say yours did the same thing, was it sudden or did it slowly come about? What were the symptons?

 

did you run at idle, or run while gunning pasted the power loss point?

If the plug isn't complete, the idle exhaust may be getting by, but a higher rpm expulsion may not get by.

Did you remove the 1st O2 sensor as previously suggested? pop it out, drive it around, a little bit, and check the power. then check the cat to see if it's glowing when you get back.

 

ok, took the O2 sensor out, no difference. It seems to be getting worse. I cannot drive it because it has such poor power; it want accelerate above 1500 RPM's. I can watch the O2 sensor while running and its flipping back and forth between lean and rich during idle but it starts staying at rich the more I accelerate. I also spray some more fuel manually into the throttle body and I get no extra speed, like its getting all the fuel it needs and more doesn't help. I have also tried manually rotating the TPS to put more fuel into the engine but seems to make no difference or it makes it run worse and kills the engine. I'm begining to wonder about the coil or distributor cap.
Any more thoughts?