Trottle body/MAF cleaning troubles

After a good amount of time with rough idle and dealing with it, and just recently an even lower and rougher idle (died a couple times), decided it was time to take a look at the throttle body and clean both that and the MAF.

First time doing both, had resurrected the engine from severe mistreatment a good year ago. Looked as though the previous owner had never changed the oil, sludge in the engine like you wouldn't believe.

Took the throttle body off and sure enough--S*** CAKED on everything I could see. Was able to clean it up pretty good and put it back together. Also took the MAF out and sprayed legitimate MAF cleaner to eliminate any doubt. Here is what followed:

1. Started up, just fine...
2. Realize it's running fast
3. Realized I forgot the MAF sensor, connected the MAF sensor.
4. Hesitates a little bit.
5. RUNNING LIKE MAD, idle at 3,000 rpm
6. Throttle not settling all the way back
7. Ran 7 miles back home, idle still at 3,000 rpm.
8. Shut down, still idling just as high if not a tiny bit more
9. Here I am

Any ideas? I could tell that the throttle body I took off was not the only air system part that needed cleaning, that was for sure. Was it just too much a change for it to catch up to? Will it just settle down after a little more time?

 

Any codes coming up? How's the spark plugs look

 

Check for a little slack in the throttle cable (at the throttle). There should be a little.

 

This is the 4th time in as many months of serious problems after cleaning the MAF and TBI.

How did you clean them, and more importantly, why?
The MAF should never need to be cleaned unless it becomes fouled or dirty from the use of a "washable" air filter.
The only thing that should be needed is an occasional "wipe down" of the inside of the throttle bore and butterfly using a clean rag soaked in Seafoam.

 

Unplug the battery so the ecu can reset.

 

Think about this...if it was as caked as you say, it wasn't getting much air through there. When you cleaned it, all of a sudden it was getting a lot more air at idle. Iac is probably confused, as well as the PCM. If it was as bad as you say.

 

Haven't a chance to look at either. Check engine light was on before this started, will have to run and see what I find. Would spark plugs really play a role in this?

Yes, there is slack. I actually disconnected the throttle cable, albeit it's lower, it's still at 2k rpm. Connected the cable, no change.

After my findings on the sight, I thought this would be a good action step to help minimize or solve the issue. I took the MAF and sprayed with MAF cleaner and let it dry. The throttle body was filthy, picture below, so I cleaned as advised (throttle body cleaner & seafoam with a tooth brush)

Did this, seemed to have improved slightly. from 3k to 2k...

That's what I was thinking as well.

Disconnected the battery as advised and disconnected the throttle to see how it would idle without it. Now, it's stuck at 2,000. Put the throttle cable back on and it sits right around 2k. Better than before, but still a good 1,000 rpm where it should be. Attached is the picture of the body before I cleaned it... I was able to get most of it off with the exception of a semi-circle's right where the butterfly pivots.


Running to see if I can get some codes, any other help appreciated

 

Update: Took it for a run...quickly back up to 3k rpm's. No Check Engine light to speak of.

 

x2

 

2nd gens dont have cables.

EDIT: Jk I just saw you had a 97

 

High rpm after throttle body cleaning is normal, but 3 gand is a little high. How does the truck accelerate? Is it smooth or jerky? Check if there is any gunk on the edges of the throttle body butterfly which could keep it from closing to it's idle position.

Also, if throttle body and intake were very dirty, maybe even check your PCV valve vacuum lines etc.....

 

wut engine ?

(* already mentioned) IAC (idle control valve) if ya have one

It can be cleaned... but could need replacement if that don't work

the fsm details the resistance check/test

 

2.7

 

Codes or no codes

Are you certain all connections are clean and seated for wiring items.

My guess would lean towards you got debris into the Idle Air circuit and need to flush it out or remove and clean it.

Also, any chance you somehow left a hose undone creating a crazy vacuum leak?

PK

 

Update: After my last post, I quickly found my air cleaner assembly to not be connected completely...dope! When not move, the engine idles right at 2k rpm. As I am coasting and off the gas, the engine bounces between 1k and 1,500 rpm. It's like a constantly bouncing basketball. Once I stop at a light, etc, it goes up to and stays at 2,000 rpm.

Ran like this for a few days with NO codes. Running down the highway on Wednesday, Check engine light pops up. Made it to AutoZone, 3 codes came up:

401: EGR?
130: o2?
133: o2?

I replaced the plugs and wires with no difference. Didn't think it would, but thought it was about time anyways.

Stays at 2,000 when still, consistently bounces between 1k and 1.5k when coasting...

 

Sounds like a vacuum leak but a new O2 sensor wouldn't hurt.