86 740 sputtering / shaking on take off

e777 · Post by **e777** » 13 Jan 2010, 18:05

This 86 740 wagon has 235k. I bought it for $325 as a parts car but it turned out to run so nicely that it is a driver now. That is, it ran nicely until a couple of weeks ago. I was stopped at a stop sign and I noticed the car began to shake when idling, almost as if it wanted to stall. It shook more violently when accelerating and continued to shake and sputter (with low power output) until I reached about 20-30mph. Above this speed it runs fine and accelerates nicely. The problem is aaccelerating from a stop or at lower rpms (under about 1500). When consulting the archive, this problem seems to frequently be related to the air mass meter.

Here is what I have done recently:
- new fuel and air filters
- clean air mass meter with CRC cleaner; I did this without taking the unit apart. I sprayed the components through the screen very thoroughly

This did not do the trick. Any suggestions?

Cheers,

Eric

Post by **billofdurham** » 14 Jan 2010, 12:41

Check the connector to the air mass meter for good contact and corrosion.

Check the condition of distributor cap, rotor, spark plug leads and spark plugs.

Remove each spark plug, earth (ground) the threaded base against the engine block and, with the spark plug lead connected to only that plug and held in insulated pliers, have someone crank the engine. You should see a spark. If not, there is a problem with spark delivery. Repeat with each plug/lead.

Are both fuel pumps working?

Check fuel pressure.

Bill.

e777 · Post by **e777** » 14 Jan 2010, 19:26

Thanks, Bill. I have had no problem with the fuel pumps. Starting has been easy. Of course, not knowing the history of the car, I guess the pumps could go at any time. I do need to verify fuel pressure. For good measure I also cleaned the throttle body.

I did check the plugs and they are quite tired; the rotor and cap are charred. I will replace and let you know what happens.

Thanks again,

Eric

e777 · Post by **e777** » 31 Jan 2010, 12:16

Bill, you were right. It was the cap, plugs, rotor, and wires. A couple of the plug tips has literally turned to powder where they connect to the cord. No more sputtering / almost stalling. Glad that I don't have to mess with the fuel pumps...yet.

Thanks a lot!,

Eric
86 740 wagon 235k

Post by **billofdurham** » 31 Jan 2010, 12:28

You're welcome.

Thank you for the update.

Bill.