I have a 95 trooper 3.2 V6 SOHC.

It has started dieing, and wont restart and stay running for a while. It will crank and start running for a couple seconds, then die at ilde. After a while it will run again normally. This may happen once every day or two. All kinds of dash lights come on when it quits.

Sometimes it now will also lose power/sag when accelerate hard. (which seems like restricted fuel, possible bad TP?)

It has codes 44(lean O2 sensor) and 32 (EGR system). I have cleaned the EGR, it seems fine.

I replaced the fuel filter (had some problems with crap in past 2 yrs since ethanol got added to gas). Fuel pressure measure 42 at idle with vacuum hose off of regulator, drops to ~36 with vacuum hose connected.

any ideas? Seems I need a scan tool that can read the troopers OBD1 to tell more, but dont have one or know where to get it.

It sounds to me as though you have the classic intake manifold gasket problem.

Could be, although the IMG problem was more common in the 98+ motors...is there any difference in the way it runs at cold start (before warming up)?

MORE COMON FOR THE FUEL PUMP TO BE DIEING, THAT ENG HAS SHEET METAL INTAKE GASKETS,AND ARE VERY THIN BUT VERY STRONG, THE LATER ENGS HAD THE MIKARTA (PLASTIC ) INTAKE GASKETS AND THEY WOULD BLOW OUT AND CRACK, IF OVER TORQUED EVEN A LITTLE, I HAVE NEVER SEEN ONE OF THE OLDER STYLE GASKETS LEAK OR BLOW OUT , BUT I GUESS IT IS POSSIABLE JERRY

My trooper has had this happen twice. Once was a bad ground. The other was a battery with collapsing plates.

it runs better I guess totally cold sometimes, then after a few minutes when you step on the gas, the engine sags, and the transmission sometimes starts hunting and jumping around.

i did the fuel flow test, got .62 liters in 15 sec vs the minimum .38 liter/15 sec that the manual states, so I dont think the fuel filter in the tank is crapped up. I changed the fuel filter and had no benefit.

My wife said one time when it died, it wouldnt even turn over to restart ,all the lights were dim on the dash, etc. A few min later it worked fine. I think there is more than one thing going on. The sag and codes have been around a while (i dont drive it, she does so I didnt really know how bad it was), and the dieing and not restarting is new.

Sounds electrical. Disconnect and clean all battery/starter/alternator connections, if that doesn't cure have the alternator and battery tested.

I cleaned the battery connections. It has not died since that. The Neg was pretty fouled.

I replaced the MAP sensor, very noticeable improvement in idle with that, the noisy valve lash adjusters got immediately much quieter, I think the MAP was causing lean running sometimes. Replaced the throttle position too, dont think that did anything.

I test drove it about 80 miles today, constantly accellerating HARD, then decellerating, for most of time it did nothing. Then sometimes it will start surging/bucking under full kickdown acceleration after its been running a while. No codes after this either.

This is not totally disabling at low rpms like it was before I changed the MAP. I do think the MAP was part of it.

I ran it with the O2 sensor disconnected too, no difference. I was hoping the O2 sensor was jacking it around but with it disconnected it should run open loop and not be a factor.

Any ideas??

My valve cover gaskets leak badly, Im going to change them. I have noticed that the engine doesnt drop rpms like I recall it used to when the oil cap is removed from running engine. I think the PCV valve is bad too, but I have to order it.

No codes or check engine lights with the O2 sensor disconnected?

If the O2 sensor is the culprit it should run good cold (open loop) until it warms up and starts taking the bad info from the sensor...it also should run good on full throttle accel, as the sensor is out of the loop then too.

of course there was a code with the O2 disconnected. I did that separately.

I ran it in diagnostic mode and could see from the flash rate of the check engine light that during heavy acceleration it was open loop anyway, and thats when the surging occurs ...sometimes.

The oil pressure gauge has started going to zero at idle..sometimes, as soon as rpms increase a couple hundred it jumps to where it needs to be, about 1/2 way to the 85 psi mark. Might stay there when go back to idle, or might drop out to zero again, Seems like something electrical affecting that too. I unplugged the sensor to check connection and it was very clean.

Im running out of ideas here. Maybe Ill buy a new coil and swap around to see if that helps. Engine coolant temp sensor too.