87 lesabre problems....need ideas

[StewartFan20]

(3.8v6)

Let me start from the top with how this all started. One day out of the blue a few weeks ago the engine would sometimes stall on me at an idle. It would crank right back up and run fine and randomly shut off at idle again. Wouldnt do it all the time. Anyways, the more I drove it, the worse it began to get and the more it would shut off.....but no ses light yet. A few rides later and I tried to use the cruise control and it would work but the engine would stumble when the engine wasnt pulling so I had to turn off the cruise. By now, its stalling anytime I let off the gas to stop or turn or let it sit and idle for more than 15 seconds or so in park. Well, yesterday, it FINALLY began running real rough and the ses light came on. I pulled a code 22 for the throttle position sensor and a code 34 for the MAF sensor. I figured now that I know what it is, I can replace them and everything would be fine....WRONG. After replacing both of these sensors, it doesnt seem to want to shut off at idle anymore but it hesitates getting on the throttle from idle and sometimes I can feel a pop and some backpressure going back to the air filter box. Also, everytime I clear the computer now, as soon as I crank it back up, it throws a code 34 again. Im not sure where to go next with this thing so I hope someone can help me out here.

[HotZ28]

Code 34
3 flashes, pause, 4 flashes
There was no MAF signal for over 4 seconds while engine was running. Check for loose or damaged air duct, misadjusted minimum idle speed and vacuum leaks. Inspect the MAF sensor and the electrical connections.

This also sounds like a timing problem. How many miles on the timing set?

[StewartFan20]

I replaced the timing set around 80,000 miles or so and its been almost another 100,000 since then. I replaced the old nylon tooth sprocket with an all metal one at the time hoping it would last a lot longer. Man, I really hope I dont have to go thru replacing that stuff again...lol...That was the first time I had ever done it before and it took me about 6 hours to do it by myself. Im now looking at a test procedure on alldata to check the maf sensor circuit and see where that takes me. I'll post the results in a few minutes, it doesnt seem like a tough procedure.

[StewartFan20]

ok, according to the test procedure, with the ignition turned on but engine off I should have read between 4-6 volts from center pin to ground which I did. Next step says to take a test light and test between A and C on the terminal and the light should come on and it did. That sent me to where it says its still a faulty maf sensor. The one I bought was remanufactured so it could have been a bad one I guess. Im going to order another one tomorrow morning and install it after work. If it comes up faulty again with another one then I will know something else is up with it. Until then if anyone has any other ideas by all means please let me know.

[maxwedge]

Common problem in those years, made even more common by poor rebuilding issues, especially Cardone's units.

[StewartFan20]

You hit the nail on the head maxwedge.....its remanufactured by cardone... Good thing it comes with a one year warranty.....thats how long it needs to last before I sell the car next year. They just called about picking up the one I ordered, so Im off to pick it up and try it out and see if its going to work or not. I'll report back on what happens.

[StewartFan20]

Well, put the new one on, cranked it up, and after just a few seconds.....ses light came back on again with code 34. Crappy sensor again or should I be checking something else that could cause this code to appear?

[maxwedge]

Check the connectors very closely, try disconnecting also and see how it runs. A full scan would detect whether ther pcm was receiving the proper readings also. Recheck HotZ28's suggestions as well.

[Scrapper]

you could have taken maf apart and cleaned it but what's done is done.anyway sounds like it's out of time with it popping or backfiring sounds like your going to have to reguage cps if it's the timing.

[StewartFan20]

Just wanted to stop back by and thank everyone for the ideas. I finally got it figured out this afternoon. I went and bought a fuel and vacuum tester, and both checked out fine. aggravated from not finding anything there, I started re-testing the voltage on the TPS and it was off, way off. I had set it to .520 volts when I installed it and when I re-checked it today, it was reading milivolts until 3/4 open throttle. Exchanged it and put on the new one, set it and it runs like a sewing machine again. Hasn't ran this good in quite a while. I'm beginning to believe that buying NEW parts instead of remanufactured is the way to go. Might be more money but the headaches of getting bad parts is starting to make it look worth it to me.