86 Astro losing power on acceleration

[truff]

Hi, everyone. My 1st post here. I googled my problem and low and behold I end up here. Wow, theirs a wealth of info in here, and I could probably find my problem if I persued enough but what the hay, I'll go ahead and post my problem anyhoo.
I drive an 86 Astro that recently had a rebuilt Jasper Engine installed last year. (6 cyl. - 4.3 Litre ?) I just changed the oil, installed new plugs, cap and rotor, plug wires, due to the fact that the orange "CHECK ENGINE" light came on when it started running rough, and thought that I might have fixed the problem but guess what ? "eeern't!
When I had the Jasper motor installed,new pcv, egr, oxygen sensor, map sensor, etc. were installed. I drive about 55 miles a day round trip to work, by the way.

Anyway I'm attempting to get a few ideas as to what else it could be before I venture down to the local garage and have a mechanic charge me 100.00 to run a diagnostic on ole Bessie. Any tips or suggestions would greatly be appreciated. Thx, Tom

[Kings-x59]

You should be able to pull the code or codes yourself. All you need is a really expensive OBD I diagnostic tool called a paper clip.
Below the dash, to the left of the steering column you will find the assembly line data link.
goto this link for a diagram http://www.autozone.com/servlet/UiBr...3d801188ba.jsp
Bend your paper clip, er diagnostic tool, into a hair pin. With The Engine OFF. plug one end of the clip into terminal A and the other into Terminal B.
Turn the ignition key to the "on" position. DO NOT Start the Engine.
The service engine light will flash one time, then two times. This is a code 12. It will repeat this sequence again two more times. This indicates the PCM is working correctly. The next series of flashes will give you the codes, for example two flashes followed by three flashes is a 23. The PCM will flash each code stored three times. When you see the code 12 again, the PCM has returned all the codes.
If you don't get it the first time, repeat the process. The codes remain stored until cleared. The codes remain stored even if the service engine light only lit for a short while.
Once you've pulled the codes and corrected the problem, the pcm can be cleared by disconnecting one of the battery cables for a minute.
Pull the code or codes and post your findings here. I have, and many others here have the list of trouble codes.

[truff]

Thank you, Kings x.
It worked exactly as you said it would.
Code 44.

[Kings-x59]

ok code 44.
The symptom indication is lean exhaust.
One of the probable causes you've already addressed, the O2 sensor.
another probable cause is a vacuum leak, so start with the cheap stuff first, the hoses. check to make sure they are all well seated on their fittings. trace over the plastic hoses with your hands - i've found 3 inch long holes that I couldn't see worn into some of mine. Pull each end of each hose, one at a time off its fitting and check for splits. With a 1 year old rebuilt engine, I'd think you'd have all new hoses, but you never know. And, one might have just popped loose.
Another vaccum leak source is the gasket between the TBI and the manifold. Since your engine is rebuilt, I'd think the TBI gasket would be new. If you have a torque wrench set it to 12 ft/lbs. and check the torque on the three bolts holding the throttle body down. If you don't have a torque wrench, turn each of the three bolts about a 1/4 turn and see if there is any improvement.
The next probable cause is the intake manifold gasket. if there is a serious problem with manifold gasket you'd be having other symptoms. Again, check the torque on the intake manifold bolts.
If this is an '86 four cylinder, get a Haynes manual (I forget, 12 bucks maybe) and a torque wrench (20 or 30 bucks). The '86 four cylinder intake manifold has 7 bolts with three different torque settings.
If it's a V6, the torque settings are 15 ft/lbs to all the bolts, then 35 ft/lbs to all the bolts.
The last probable cause is the connections to the computer. I think this one is unlikely, but if the your '86 is similar to my '89 the pcm is behind the kick panel on the passenger side. Get a Haynes manual, it helps a bunch with getting to the pcm. I had to remove some duct under the dash and the kick panel to get to the pcm. I hate removing interior trim. I usually manage to break something.
You have my sympathies on your commute. Mines about half yours and it sucks.
good luck. my gut feeling is you've got a vacuum leak somewhere.

[truff]

(by the way, my Astro is a 4.3 / 6 cyl. / auto.)

Well, I purchased the 02 Sensor today and will install it tomorrow. I'm guessing that all the vacuum lines are new but I'll take a look at things much closer under the hood tomorrow. (vacation day)
I'll let you know what I find and thanx again for all the help. This forum is A-1, plus I've been telling my friends about it too.

[Kings-x59]

hmmm - thought the rebuilt had a new O2 sensor already. But, it could be the O2 sensor. I had a new TPS crap out on me.

[truff]

Well, I replaced the 02 sensor, and checked all the vaccuum lines. Let me tell ya, removing the 02 sensor was a bear. I ended up using an acetelene torch to heat up the exhaust to finally loosen the bugger. I believe I went over thoroughly the entire vaccuum system including the cruise control lines as well and didnt find any leaks. I then disconnected the battery for at least 15 minutes and went on to work somewhere else for a while , came back and reconnected the battery and drove the van for a few miles. At first it seemd better but then the check engine light came on again. So I proceeded to do the paper clip trick and this time I got a code 44 AND a code 43 ? Any idea what that means ? Thanx in advance.
*edit*
I just found these codes on another gm site :
43 Electronic Spark Control unit (ESC)
43 Throttle Position Sensor (TPS) out of adjustment
43 Front oxygen sensor rich (Cadillac FJI)
43 Knock sensor signal
44 Oxygen sensor or circuit - lean exhaust detected
....so all I need to do now is figure out which of the 43's above is the problem ?!

[Kings-x59]

My manual for the Astro shows code 43 to be the Electronic spark control unit.
Before you go buy more parts, check the connections at the computer (PCM).
Also, give the three bolts holding the throttle body a slight turn to make sure they are tight - this could be the source of a vacuum leak.
If the gasket under your throttle body has never been replaced it probably looks like mine did - a bunch of black mush.
Again the indications for code 44 are:
PCM connections
vacuum leakage at the TBI base gasket
vacuum leakage at hoses
vacuum leakage at the intake manifold gasket
O2 sensor.

[truff]

When you say check connections @ the PCM, are you referring to the plug outlet under the steering cloumn ? Or is it located elsewhere ? tx, Tom

[Kings-x59]

Nope, it's a bit harder to get to than that.
it's behind the passenger side kick panel just in front of the passenger side door.
Go to your local autoparts store and get yourself a Haynes manual for your van. You need some pictures and some step by step sequences. It'll help to keep you from breaking panel clips ( like I have done sooo many times)

If you are serious about doing this stuff yourself, the cost of the manual will be recovered in short order. Between the manual and the forum here, you'll be in good shape.

[truff]

...its amazing what replacing a fuel filter does. It made all the difference in the world
Thanks for all the help, Kings X, et.al. Sorry I didnt get back here sooner. I've been having too much fun running around in my 86 4.3L V-6 Astro, now that it runs like it's supposed to.
Til I encounter another problem with ole Bessie, cheers to all. Tom