92 GXE Auto, 197,000mi. Had been sitting for a month...

Car ran fine for 10 minutes.

Heat guage started fluctuating/dropping (too cool, never too hot).

Developed slight "bucking" under load/acceleration (Tach Dropped during bucking at least once).

Bucking under load got severe - car stalled.

Check Engine Light came on.

Re-started/stalled a couple times.

Could drive home (40mph) as long as I never tried to accelerate or push the gas much. If I hit gas more than a TINY bit, the car would buck/stall.



--my guess-- car running rich due to incorrect engine temperature readings by ECU.


I need to fix it this weekend - - ANY IDEAS!!!?!?

I appreciate the help!!

 

maybe engine temp sensor

 

Shot in the dark here...but I had a car do that a few years ago and it was a head gasket...check your oil for antifreeze in it.

Another shot is to get the codes pulled and see if the computer is showing a bad sensor or something...

Good Luck! Joe

 

I assume the car was running fine before it was sitting for a month? How's the car at idle when it's warmed up?

 

At idle, the car seems to run ok, though it will occasionally stall. And, yes - the car was running fine before i parked it for a month.

(head gasket!?!? now you've got me all nervous!!!)

 

dont worry about the head gasket too much i BLEW mine on my trans am and she still did burnouts downt he block till i let my foot off the gas. however your first step is to see if the computer is telling you anything, take the easy step first, go to nissan and have the codes pulled (if any), then troubleshoot from there. and a head gasket isnt that big of a deal ive done plenty of them - and yes they ran after i stared them to the smart A$$ES here...

 

Since your temp gauge was acting strange, Subs1000 was probably on to something with the temp sensor. I think there are two different parts (ask Internetautomart, who also sells them).

I know that VGs seem to go through MAF sensors more often than VEs -- you might want to try and swap one with someone to see if that might be the problem.

Other than that, go straight to the codes.

 

You definitely need to pull the code/s first and then go from there.
the car should have 2 temperature measuring devices.
1. Coolant temp SENSOR, probably what's bad, it tells the computer what temperature the engine is running at and uses that to calculate the correct amount of fuel to put in.
2. Coolant temp SENDER, sends the signal to the gauge on the dash.

 

are these two items easy to get at?

 

I had the same problem with my Z a few years ago. Turned out the sensor sending coolant temp to the ECU was bad and the ECU thought the engine was cold and flooded it with gas, which accounted for the stalling.

Both sensors were easy to get at with the Z, with your car it should be even simpler. There should be a metal pipe running from the radiator towards the engine with those sensors sitting right on top of it. If you locate it, disattach one (don't take it out the pipe of course because you'll have coolant fluid all over your engine bay, just disconnect the electrical plug) and see what happens. If the gauge on the dash stops working, the OTHER one is the one you're looking for. Turn the car off, take it out and check if it looks clean. If it's corroded, that's your problem.

Or, a simpler yet less meaningful test - have somebody take the car up to 4-5K rpms and abruptly release the throttle. if you see a puff of black smoke in your pipe, you've just seen a bit of radiator fluid burn off.

Or, simpler yet - if you've driven your car around a bit with this condition, yet the radiator fluid level is fine, all the way up to the filler cap, your head gasket is most likely just fine.

Also, the electrical plug itself may be corroded (that was my case). An old toothbrush and some WD40 will allow you to get up and running in minutes.

It's not the head gasket, I'm 90% sure of that because the car would not die from it, rather run badly. To test the head gasket (and it is the simplest and most effective test you can DIY, start the car, open the radiator cap, stick a funnel in it and put some radiator fluid it it, say until it's half full. then pull the throttle cables. If there are air bubbles coming out to the surface of fluid in the funnel, it IS the head gasket (man, when my had mine bad and did this, the bubbles were so severe fluid was fountaining from the funnel, creepy sight!). But your symptoms do not suggest that this is your problem.

Good luck.

 

anybody else??


going to work on the car tomorrow.

 

Well when my car started the hesitating and surging I took it for a diagnostic test and got codes for a bad fuel pump, o2 sensor, and a vehicle speed sensor. Being that it can't be the vehicle speed sensor or the o2 sensor I'm going to change the fuel pump and then the spark plugs and see how it goes. Process of elimination !!