Hi guys i have a werid problem,
i have a 2004 dodge ram 1500 5.7 hemi and when im driving an get to speed about 50 and the rpms drop to normal which is 1500 or less, its starts to pulse for example my speed at 60km an holding steady rpms at 1450rpm it will pulse between 1200- 1450rpm.. it does not give me a check engine light i have no idea what it is? anyone can help please.... ???

 

I don't know if this is a recent problem for you or if you just got the truck. If new to ram's, at 60km/h you'd be shifting into OD (4th and 5th) and it's probably bouncing between 4th/5th and/or torque converter trying to lock up. Can't select drive on the 04's but if you turn your tow/haul on, might not be as bad running no higher than 4th gear OD, At least this way it won't try to get into the second OD gear which is really low on these trucks.

 

Thanks but ive had the truck for 2 years this is the first time it has done it. even when in park you can heard it do it if you put the gas at a steady 1500rpm. it does it more once it warms up ive noticed.

 

could be a very very small vacuum leak too. If it gets worse over time then my bet is a vacuum leak somewhere.

Otherwise it might be time for a new air filter and/or spark plugs...