Good morning folks!

I'm relatively new here, and I need some help. I've searched a lot of threads for this, and have a few more things to try, but want some fresh opinions here.

I have a 2003 Ram 1500 Hemi 4x4 Quad cab automatic. I've owned it for a year, and bought it from the orginal owner. It has 242,000km (130,000 miles). Last week under fairly heavy acceleration merging onto the hiway (trying to get ahead of a semi), she started bucking once she kicked down. I was at 100kmh (60 mph). I backed off on the gas a bit and the bucking went away. The only time I can replicate the problem is under heavy acceleration when it drops down 2 gears, then it bucks like someone is jumping up and down in the bed of the truck.

Here's what I've done to try and fix:

new air filter
new plugs (all 16, champion copper, gapped 0.040)
carb cleaned the **** out of the TB
took off diff coover, flushed out old fluid and replaced with Lucas 75w140 synthetic
ran a can of seafoan thru a 3/4 tank of gas.
inspect u-joints, a little rusty so need to lube, but look good

still bucking, so here's whats next:

EGR clean or replace
transmission flush and replace filters


What else could it be? Any help/advice would be greatly appreciated

 

EGR could make it buck, but if it's that blocked up I would think it should have generated a CEL long ago.

Probably on the right track with the tranny fluid replacement...

 

By chance, any check engine light?

 

That's the maddening part about it...b!tch won't throw a code for me so at least I have an idea where to start looking! And no check engine light either...nothing to point me in one direction or another.

The way I figure, it's a 9 year old truck with higher mileage, so things are going to need to get done. I'm fairly mechanically inclined (done a lot of my own stuff on my bike and other cars in the past). So I guess this is just a good excuse to go through it now that summer is more or less here and get all the maintenance stuff up to snuff. I just hope it's nothing too involved, I don't want to have to learn how to replace a transmission quite yet!

 

No EGR on the 2003s, or is it different on the 4x4? Do a full Sea Foam treatment ('cept for the oil). Weird there're no codes

 

nope, there's definitely no EGR on my '03...THAT would have been too easy! Guess I'm back to running another can of Seafoam thru her until I can do the tranny flush.

BTW, what's the best recommendation here: professional flush and refill with new filters, or just drop the pan drain it myself?

thanks!

 

Drop 'n' drain and new filters. Doubt if that'll cure the bucking, though.

 

Check fuel PSI.
Whats the RPM when this happens.?
Does it cut out from the PCM from over rev??

 

Could be a mass air flow meter. They measure the air coming into the intake and calculate the load based on the air coming in. They don't always throw a check engine light but will cause drive ability problems like you describe. Try even disconnecting it and see what happens.

 

thanks for the suggestion, but after surfing the site I found out our trucks don't have an MAF. no EGR valve either. looks like TPS is next.