Mechanics

LOSS OF POWER WITH MULTIPLE CYLINDER MISFIRE AND OTHER CODES

1997 Dodge Ram • 15,500 miles

Hi, sorry this is gonna be long, I have a Ram 1500 SLT 5.9L. Been having power issues for a while, now it has gotten much worse. Started when trying to pass someone on the freeway and when giving it more fuel it bogged down and lost speed until I let off the accelerator and then reapplied. CEL came on showing codes for 3 cylinders misfiring. Never felt like there was a power issue unless I was at freeway speeds in the same situation. Later it died when pulling through a drive thru and would not start back up. Towed it to a shop and they replaced the computer stating it wasnt converting voltage right. Truck ran fine for a while but would still have the power loss issue at freeway speed. A month in a half ago transmission was going haywire, over drive system was not functioning and truck started safe starting in 2nd gear. Took truck to a tranny place and they rebuilt the tranny stating the electric components and overdrive system were fried. Got it back ran decently except now regardless of speed or rpm the truck would lose speed on hills whereas before it could tackle any hill as long as it was running over 2000rpms. Still had power loss issues when applying too much throttle. Got even worse as of late and it could barely hold 50mph on the freeway and 30 mph on local roads. Let it sit a few days and drove it again and it started bogging down again at the end of the drive even at low speeds. Barely any power to get up hills with straining to get to 15-20mph. CEL would flash anytime it I tried to give it a bit more throttle but the rpms would rise normally. Still showing the same misfire codes for the same cylinders and check the flashing CEL against the book and it shows (3) code 33's - open or shortcircuited condition with the speed control vacuum, (1) code 34 - open or shortcircuited condition with the radiator fan low speed clutch ( I think) and (1) code 35 - open or short circuited condition found with in the a/c clutch. Took it to another shop they said I should take it somewhere to get the catalytic converter tested eventhough there was no unburned fuel or raw eggs smell coming from exhaust. The next place I took it to said the spark plugs and wire looked bad and I should replace those, so I took it home and replaced the plugs, wires, distributor cap and rotor. The CEL went off but thats probably just from disconnecting the battery but all the same power loss issues are still present. Any Ideas?
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Heelsusmc
July 12, 2012.



From the missfiring, I bet the converter is bad. A simple back pressure test will confirm.

Roy

ASEMaster6371
Jul 12, 2012.
What do I need to do a back pressure test, Ive read on other forums that if I disconnect the O2 sensor before the converter and drive it that if the issues are gone then the converter is probably plugged.

Tiny
Heelsusmc
Jul 12, 2012.
You need a back pressure gauge and install it where the downstream o2 goes. You dont have to drive it, just rev the motor.

Roy

ASEMaster6371
Jul 12, 2012.
Ok thanks, ill see if I cant try that tomorrow. Any idea about why im getting those other 4 codes?

Tiny
Heelsusmc
Jul 12, 2012.
The codes indicate electrical issues. You need someone with a good sense of electricity to help track down the failure.

Roy

ASEMaster6371
Jul 12, 2012.