I have a 92 mitsubishi galant that starts cutting out after driving for awhile. Does not happen on short distances, but will randomly happen on trips over about 30miles. The engine just starts cutting out rpms go down, but will come back up, car bucks as rpms go up and down, car will idle fine but power cuts in and out above idle. I can put the car in neutral and cut the engine off, start it back up and sometimes this will fix the problem temporarily. but, the further you drive the more it occurs. I drove the car to work (60mi round trip) tues, wed, thurs, and today. Thursday and today were the only days it messed up this week.

The Long History of the car
My grandpas sisters hurband had this car, I think he bought it new. Always took good care of it and had it serviced regularly. He died in 04. He had stopped driving it shortly before he died because it didn't run right after timing belt was replaced. My grandpa's sister gave the car to me in 05 and we found the timing belt was 1 tooth off. Installed another new timing belt and it now ran fine except it smoked and had a bad oil leak. Installed new valve seals and oil pan gasket to fix smoking and oil leak. Took it for a test drive and heard a noise and then a rubbing noise from timing cover. pulled it off and the balance shaft had seized and popped the belt for the balance shaft and then rubbed the timing belt. Installed a balance shaft eliminator kit and another new timing belt and all was good. After driving the car a long distance I noticed this cutting out problem. I replaced fuel filter, air filter, tps, full tune up, coil, and throttle body (used), also checked the ecm. Also it has intermittent high idle problems, Replaced the IAC with several used ones and still has the idle issue. I got tired of working on it in 05 and parked it in the barn. I would start it up and drive it about once a yr. Got it out last week and cleaned iy up, changed the oil, checked all fluids and realized the trans would not shift, replaced the tcm and that fixed the trans. I'm thinking it may be the fuel pump. It was cutting out really bad today, gas tank was just below 1/4 tank, I added 2 gallons of gas and it was much better, (it wasn't out of gas). I think the fuel pump may be overheating and dropping fuel pressure. Adding the gas cooled it down enough to make it better.

Any help with this problem would greatly be appreciated.

Thanks, Michael

 

that model galant 89 thru 92 were FAMOUS for the PCM'S going out. caused all kinds of drivability issues, including your issues. also there were a few distributor failures. check engine light on?????

 

no cel, i checked the ecm 5yrs ago when this all started and capacitors were good, but i replaced the capacitors anyway. I checked it again and everything still looks good. Is there a fuel pressure test port? i didn't see one. is there any way to test the distributor?

 

Went for a drive yesterday and normally it takes awhile to start cutting out. I went for a 10 mile drive and drove it hard, accelerated fast at each stoplight etc. It gradually started stuttering at higher rpms and progressively got worse. Just for the heck of it I pulled the vacuum line to the fuel pressure regulator and plugged the line and drove it. No change whatsoever. I was just below 1/4 tank of gas so I stopped and added a few gallons. It still cut out afterwards at higher rpms but was much better.

 

I got an extra fuel line and spliced in a fuel pressure gauge. I can't see it will I'm driving and it's cutting out but it stays at 43psi idle. If I rev it sometimes I can get it to dip below 40psi. From what I can tell pressure should be 43psi. If I remove the vacuum line to the fuel pressure regulator, pressure goes to 50psi. Seems to me the pressure should go higher, but maybe not?

 

fuel pressure is on the mark. have you replaced the fuel filter?? i have also seen the filter on the fuel fump get clogged, some people call it a sock, get partially clogged. no realistic way to check the distributor unless you have a scanner that shows real time data. definatly can be a problem.

 

I put a longer hose on my fuel pressure gauge, so I could see it while driving. When it would start to cut out fuel pressure was around 30psi. When it really cut out it dropped bellow 20psi. I picked up a used fuel pump assembly from the junkyard for $54 with a 6 month warranty. I swapped it in Sunday and when I pulled the old one out the sock was plugged up. I went ahead and used the junkyard fuel pump and sock and so far everything seems good.