Post Throttle Body Cleaning

I have a 2008 Ram 1500 5.7L Hemi, which I've had since brand new. It's been due for a throttle body cleaning as the throttle response hasn't been too great. Today I did its first throttle body cleaning at 75k miles. I removed the neg terminal before removing air intake tube and sensor plugs, then removed the throttle body.

I used CRC cleaner with the throttle body off the truck. Once I removed the buildup (interior side was pretty bad) I put everything back together. Started up instantly with no hesitation and I let it idle. All seemed normal. Once I drove it, I immediately noticed a real delay in throttle response.

Throttle response is just sluggish. Moreso than it was with the dirty TB. Idle rpms stay at around 800, but I see them fluctuate between 1200 and 1000 when driving at city speeds (35-45 mph). The biggest issue is the drop in RPMs when I hit the throttle a little harder, in addition to a drastic drop in MPG reading. I used to idle at and read 10-11 MPG, yet today after the TB cleaning I dropped all the way to 4 mpg.

I'm now wondering if maybe there's something like a gasket out of place, vacuum leak, or if I damaged the TB in some form.

If anyone has any ideas what the issue could be, I'd greatly appreciate your replies.

Sent from my Pixel XL using Tapatalk

Just speculating since I'm not as familiar with the 2008 Hemi, but the Gen IVs have a plastic intake manifold. It only take a bout 5lbs of force in a crisscross pattern. If you over torque the TB bolts you can strip out the threads and cause a vacuum leak.

I believe the 2008 also is supposed to have a TB gasket, so that may require replacement as well. Check with A1 or All Mopar and the parts list will let you know.

I believe CRC is an aerosol cleaner. While it evaporates quickly and the mfgr claims it will leave no residual behind, everything I've heard about cleaning TBs is not to use directly applied aerosol cleaners (especially products identified as TB Cleaners). Instead, you should use non-chlorinated brake cleaner on a clean rag to work the build-up off without letting liquid get into the electronics and use Q-tips for tiny areas.

The Hemi drive by wire system TB system also needs to be calibrated with a specific procedure after reinstallation.
1.Turn the ignition to the "on" position.
2.Leave the ignition switch in the "on" position for a minimum of 10 seconds before first start after cleaning to allow the PCM to re-learn the electrical parameters.

My operating theory: You are having problems with the TB because liquid cleaner carried dissolved crud either into the electronics, or at least left residue around the mechanical interface that is impeding the stepper motor from controlling the throttle plate properly in response to signals from the PCM. The computer is then responding to erroneous feedback causing unexpected behavior..... You're not getting codes, but that may just be a matter of time.

Its a theory anyway...

Thanks for your reply. Yes, the 08s also have a plastic intake manifold. In hindsight, I should have torqued the TB bolts instead of just using a standard ratchet. I guess I know of so many people who've been fine without torquing them down, that I felt confident about it.

I basically tightened them to maybe a quarter past hand tight in a criss cross pattern. No slipping or stripping that I can tell, but then again it might have been undetected. I also did the procedure with the ignition to on you mentioned right after I put everything​ back together. Took it on the highway today, got up to about 3000 rpms, but it isn't responding like before at all. No codes as of yet.

Additionally, I overlooked the actual gasket on the intake manifold to the throttle body. I didn't even inspect it. Is it possible it got disturbed during the removal and replacement of the throttle body? I didn't think it would cause it does sit in it's groove held in place by cutouts. It's looking like I'm gonna take it all down again and inspect.

Sent from my Pixel XL using Tapatalk

One question for you, Casper, or anyone else that may have an idea: If cleaner made it into the motor/electronics of the TB... Is it ***** or can it still be salvaged?

Sent from my Pixel XL using Tapatalk

BigEmpty said:

One question for you, Casper, or anyone else that may have an idea: If cleaner made it into the motor/electronics of the TB... Is it ***** or can it still be salvaged?

Sent from my Pixel XL using Tapatalk

Click to expand...

I lean more toward dissolved solids re-hardening and impeding motion.

I would suspect it wouldn't operate for long if the liquid got into the circuitry--kind of like dropping your cell phone in a puddle: it might not kill it immediately, but it will start to act up before it goes **** Up.

BigEmpty said:

Throttle response is just sluggish. Moreso than it was with the dirty TB. Idle rpms stay at around 800, but I see them fluctuate between 1200 and 1000 when driving at city speeds (35-45 mph). The biggest issue is the drop in RPMs when I hit the throttle a little harder, in addition to a drastic drop in MPG reading. I used to idle at and read 10-11 MPG, yet today after the TB cleaning I dropped all the way to 4 mpg.

Click to expand...

I had this same issue with my 05' 5.7L, I cleaned my throttle body and no difference, ended up researching and asking around and I changed my PCV, immediately the throttle response was changed and MPG, I haven't had and pulsations in the RPM until recently again however, It may be due to siting for long periods at a time, i'm not certain. I would check into the PCV, may not be your case but it was for my truck!

So, wait. Am I clear to do this to my 05? Mileage is poor for me, and I'm looking for ways to boost it up. Currently at 9-10 all city driving. {Headliner indicator has consistently read 1MPG optimistically ever since I got it. This is the corrected number.}

Engine mods are muffler delete with a resonator relocate and a side pipe, and a K&N drop in. Everything else is stock. Stock tire size{275/60R20}, stock pressure, stock ride height, quad cab regular bed. Maybe 100 lbs of unneeded **** in it plus 300lbs of sandbags for traction and a 50-100lb overweight driver.