poor running 911

[DanielDudley]

Get rid of the plugs. They may not be the problem, but I don't think they are helping. Do check the connection to the head temp sensor. They are awfully finicky.

[la975]

Checked the voltage. 14.3 v with no load and 13.8 v with all the accessories on. It was difficult to get a reading since the engine wouldn't rev smooth at 1500 rpm, there was a constant surge and stumble. I didn't get a chance to check for the air leak. the cylinder head sensor connection was tight. I'll follow the suggestions given by kidrock to check for air leaks. Thanks for all the suggestions. I find them very helpful in planning the next diagnostic steps.

[DRACO A5OG]

LA975,

I assume you in L.A. = Los Angeles, if so go to autos=zone and have them test your battery and alternator. their machine can diagnos if it is an alternator issue.

I had similar issues then discovered after many jumps my alternator was shot.

[la975]

Thanks for the suggestion. I'll pop the altenator out this weekend and stop by the auto store and have them check it. The battery is brand new and seems to be fine.

[TibetanT]

Just a thought, but when was the last time the valves were set and the timing checked?

Good luck with this.

[jsoderbe]

Hi,

My car didn't run that bad, and had problems starting it as well. My problem was the ground wire (or whatever you US guys call it...) between the gear box and the body. It was intermittent, some day I drained the battery completely, another day it worked perfectly.

After cleaning the connections there is a HUGE difference in how the car performs, when it has enough power in the battery!

Johan

[la975]

RUNNING AGAIN!! After all those parts a couple of squirts of Gumout did the job. Not sure what this issue was but spraying Gumout looking for a air leak solved the problem. Closest I can figure was Idle position sensor or volume air flow sensor had a dirty contact. took it out for a 40 mile run and it ran great, just like before. Thanks for all the ideas and suggestions.

[MH911]

Glad to hear your car is back on the road. My car has been in the shop for over three weeks now and he still can't figure out what the problem is. If my problem ( very much the same as yours in description ) can be resolved as easy as this, I will be thrilled. I just want to get my car back and get back out on the road.

[DCinVA]

The idle position microswitch is a probable cause. This switch tell the ECU when the throttle is closed, and the ECU delivers the appropriate amount of fuel for idle. If the switch fails it may send the "Idle" signal to the ECU even when the throttle is open, which will cause a very lean mixture, and cause the symptoms you describe. To test for the, unplug the switch, and drive it without it connected. This will raise the idle to 1100 rpm, but not harm the engine.

Hope this helps.

Dave

[MH911]

Hi Dave,

I did bring up the micro switch to the mechanic a while back. He was a
little miffed at a arm chair mechanic telling him what to check. Just
said "checked it". I'm getting pretty frustrated here. I'm about ready
to go get my car back and give it a squirt of Gumout and replace the
micro switch my self.

[rcaradimos]

Originally Posted by MH911

Hi Dave,

I did bring up the micro switch to the mechanic a while back. He was a
little miffed at a arm chair mechanic telling him what to check. Just
said "checked it". I'm getting pretty frustrated here. I'm about ready
to go get my car back and give it a squirt of Gum out and replace the
micro switch my self.

I think your on the right track... get your car out of there. Search: checking idle micro switch. Using a volt meter will tell you if its in open or closed loop; moving throttle just a bit switches mode.

[la975]

Sorry to hear you're still not on the road. One thing I learned from my experience is that the parts can test OK but the connection may be the problem. Something that has been 'tested' may still be the problem. You might check your connections.

[DCinVA]

I suggest you unplug the micro switch, and drive the car for a couple days. If the poor running condition condition goes away with the switch disconnected, replace the switch.

Good Luck.