BluExpress

I have cleaned my throttle body tons of times never had any issues.

recently I changed the Idle air control and the throttle position sensor
I had to remove the TB from the intake to remove the IAC & TPS

I clean everything looked new. even installed a new gasket.

and I have zero clue what I did wrong but it’s never idled the same since.

when I turn it on, it shoots up to about 2300 and within 2-3 seconds it calms back down to around 700 rpm and idles perfect.
In gear it feels like it’s on cruise control and accelerates on its own a little bit.

I took the TB off and rechecked all my work reinstalled and on the first crank, it idled perfect.
I did the whole idle reset 3min idle 1min off turned it back on and idled great.
Took it for a drive and instantly the idle went crazy.

I gave up and said I’ll buy a new TB

I tried buying a new Cable throttle body but everything on line is electronic

I found an identical cable TB but it shows for a 5.4 v8

I can’t find one for a 6.0 LQ4 engine

I did some more research and found out that the TB gasket is the same for a 5.4 & 6.0 engine

I went ahead and ordered it I’m hoping this solves my issues.

I love my chevy express it’s been one of the most reliable vehicles I’ve ever owned but I’m having a really hard time finding parts for this van now. I used to find anything at any local auto part store now I’m having to call 3-5 different store fronts trying to find parts

I went to buy a new used van today and interest rate was 13.5% giving 5k down
van was used with 50k miles for $43,000 USD
monthly payment was $600 it’s back to the drawing board for me.

VanKo

The rear end was an issue, but I replaced it proactively and it still didn't fix the vibration.

BluExpress

the new throttle body that I ordered, even though it looked identical.

it did not work, RPM’s would shoot to 3500 instantly.

so since I am had my original TB out, I decided to take it all apart AGAIN, Reclean and assemble using a new Idle air control and my old original throttle position sensor.

it cranked on and idled perfect, I am so happy I was able to fix the idle issue. It was driving me crazy. The van is driving AMAZING now besides the random vibration


I returned the new TPS sensor and got $75 bucks back and shipped the throttle body back, that’s $200
. So issue is fixed and I got $275 back in my pockets. Today was a good day 😅



*** UPDATE on the transmission.

Took it to another highly recommended shop, they seem very confident that it’s the wiring harness and quote is $450 to replace it.

I’m going to go for it and hope for the best.

BluExpress

Earlier in this post I complained about a
p0449 code
It’s for EVAP vent selenoid valve.

I previously deleted the code with the scanner and it went away for a few days.
It come back today so I replaced the little canister by the fuel tank.

$36 part and 30’minutes of my time and problem is solved.

How hard would y’all say it is to replace a transmission by my self ??

Triaged

Shouldn't be too bad to replace a trans in a van because it's easy to get to the top bell housing bolts with the engine cover taken off. Don't need to get the van much higher in the air in order to slide it out either because it already has a good bit of ground clearance. Just need a transmission jack.

mountainmanjoe

it's not a walk in the park. You have to remove the exhaust. Have fun with those bolts.

Triaged

I guess I sometimes forget not everyone lives where stuff doesn't rust like SoCal

BluExpress

Hmm, that sounds like fun LOL!
When I attempted to replace the header exhaust bolts, the heads ended up snapping right off. 😅🤦🏼‍♂️ It turned into quite a mission, so I just left them alone.

Instead, I opted to purchase clamps that bolt onto the block and tightened the headers down. They worked like a charm, as I haven't experienced any exhaust leaks since.

Living in South Florida, I haven't encountered rust issues, probably because I'm not near the beach. However, I attribute the difficulty to my van's age; it's a 2004 model, so it's already 20 years old. Surprisingly, my engine, which is all original with 335k miles and counting, still purrs like a baby. 🙌🏼

Now, regarding the transmission situation, I've decided to take it to a transmission shop to have them replace the wiring harness for $450. It seems like a reasonable price if it resolves the issue, and I'd be quite pleased if it does.

The shop also quoted me $3,300 for a new transmission with only a one-year warranty or 12k miles, which feels steep, especially considering I paid $3k for a full rebuild just a year and a half ago at a different shop.

Some folks recommended Monster Transmissions online, which offers a transmission with a three-year warranty, unlimited miles, and a one-year error install, no questions asked replacement warranty for $2,750. The robust warranty is really convincing me to go with them.

mountainmanjoe

installed? That's not bad


Ouch. 'F' rating. 1 star cutomer reviews
I guess you get what you pay for.
https://www.bbb.org/us/fl/brooksvill...-0653-90008419

and here you are replacing it 1.5y later.

Try Jasper or powertrainproducts.net

Expresscv

Following this to see if the trans harness solves your problem
thanks for the very detailed write ups and keeping the thread up to date on what has/has not worked etc

hope the harness does the trick