3.2L runs rough under load. Engine lugs under throttle then dies

[cabmandone]

To start, the engine ran fine this morning. I was doing some cruise control troubleshooting and had the cruise module unplugged. I plugged the cruise module back in and went for a drive. I made it out of my driveway when the engine started surging. I made it about 1/4 mile and it died. It wouldn't fire then it decided to run. When it did start, it ran but was chugging and coughing and the idle was sporadic.
To go back to how it was in the morning, I unplugged the cruise module but it's still running rough. I replaced my DME relay under the seat with a new one but the old one was less than 1 year old. It ran rough after the DME relay swap.

I took the air filter off earlier to check vacuum lines and reinstalled the filter before it started running rough. I'm going to check for a vacuum line off in the event I might have accidentally knocked one off while checking lines.

I'm not sure of the age of the engine cylinder temp sensor but it's a 2 wire configuration and I'm looking into a test procedure for it.

Any suggestions would be helpful.

[scarceller]

You could have a large air leak somewhere.

At idle remove the oil filler cap, once removed you should hear the idle change and also drop.

Also unplug the O2 sensor as it could be causing the trouble. Leave it unpluged till you resolve the issue. Having it plugged in will just make things more difficult to diagnose.

Also test the output voltage of the Air Flow meter, turn the key to RUN but don't start the engine then measure the output of the AFM and while measuring it remove the air cleaner and reach into the AFM with pencil (eraser side) and start pushing the door in the AFM open very slowly and watch the output voltage as you push the door it should sweep cleanly 0.5-4.5vdc if it erratically reads and does not sweep clean you have bad carbon track in the AFM.

Also do you have any way to know if it's running lean or rich?

[DRACO A5OG]

+1 what Dr Sal wrote.

When was the last time you changed the fuel filter?

Jim

[cabmandone]

I looked over the wires in the engine compartment but everything LOOKED okay. I started checking the speed and reference connections and then got to the top connector, pushed, it clicked, started and drove fine. I have to remember to be careful when putting my arms in the engine area. I really don't like these connectors! I believe the white connector is the cylinder head temp sensor and it was loose.

Thanks for the quick replies. I feel like a bonehead for not physically checking the connections in the first place.

[scarceller]

If that white connector was loose then the engine would be running extremely rich to the point you should have smelled the fuel.

[cabmandone]

Originally Posted by scarceller

If that white connector was loose then the engine would be running extremely rich to the point you should have smelled the fuel.

Top was down and it was a bit breezy so I didn't smell anything until I cranked it and it wouldn't start then got a flooded smell.

I've got to stop freeking out and get over my fear of all things Motronic. I've been told of the problems with this E.M.S. so it generally has me a little edgy but once cooler heads prevail it always seems to be something fairly simple to fix.

[Dave Kost]

Nice job!

Watch out for those Tyrap ends....they can cut you pretty good.

[nene]

I had the same thing happen to me. I did not put the "Clip" on one of them and the car throughout my ride all of a sudden started "putt-in"! Clipped it back, and all was good.

[cabmandone]

Originally Posted by Dave Kost

Nice job!

Watch out for those Tyrap ends....they can cut you pretty good.

Funny you mention that,




I put those on when I removed the engine from the donor car to identify which plug they went to. There is a corresponding tie on the back side too. You'd think you can't go wrong that way BUT the previous owner of the donor car had them backwards and never started the engine.

[Dave Kost]

Yea they are like razors.

They make a tool that cuts the tie off flush rather that with side cutters.