Bad miss at no load operation

CHARLES STEELE

MEMBER
1999 DODGE RAM
V8
2WD
AUTOMATIC
240,000 MILES

Engine misses when just cruising no load, but pulls good under full throttle. Engine code shows different cylinder misfire every time it happens so not always the same one. New computer year ago new catalytic converter and exhaust.

Friday, February 5th, 2021 AT 3:45 PM

8 Replies

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

Are there any additional codes other than a misfire? Next, have you checked fuel pressure to make sure it isn't too high or too low. Also, have you checked for engine vacuum leaks?

Let me know. If you haven't, here are a couple of links to help you do it:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Let me know if you have already done this. If you haven't, try it and let me know what you find. Note: If you have a live data scan tool, check the short term fuel trims and let me know what they are.

Take care and God Bless,

Joe

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Saturday, February 6th, 2021 AT 5:17 PM

CHARLES STEELE

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37 POSTS

No other codes. I am retired and only have a cheap scan for codes. Fuel pressure gauge test is okay. Have not done vacuum test.

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Saturday, February 6th, 2021 AT 11:34 PM

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

If you're sure the fuel pressure is good, see if there is an issue with a vacuum leak and let me know what you find.

Take care and God Bless.
Joe

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Sunday, February 7th, 2021 AT 5:55 PM

CHARLES STEELE

MEMBER
37 POSTS

Think maybe I found the problem. I guess the last time we went up on mountain to get fire wood we pulled the fuel vapor canister off on some sage brush it is down under the back corner of the cab. Will have to get a new one and try it.

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Sunday, March 14th, 2021 AT 2:38 PM

JACOBANDNICKOLAS

MECHANIC
109,755 POSTS

Hi,

That certainly will create a vacuum leak. Also, there should be two canisters there. Here are the directions for replacing them. The attached pic correlates with the directions.

________________________

1999 Dodge or Ram Truck RAM 1500 Truck 2WD V8-5.2L VIN Y
Procedures
Vehicle Powertrain Management Emission Control Systems Evaporative Emissions System Evaporative Emission Control Canister Service and Repair Procedures
PROCEDURES
EVAP Canister Location

see pic 1

Two EVAP canisters are used. Both canisters are mounted to a bracket located below rear of vehicle cab on outside of right frame rail.

REMOVAL
1. Remove fuel tubes/lines at each EVAP canister. Note location of tubes/lines before removal for easier installation.
2. Remove mounting nuts at each canister.
3. Remove each canister from mounting bracket.

INSTALLATION
1. Place each canister to mounting bracket.
2. Install nuts and tighten to 9 Nm (80 in. Lbs.) Torque.
3. Install fuel tubes/lines to each canister.

____________________________

Let me know if this helps or if you have other questions.

Take care,
Joe

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