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92 mitsu galant cutting out

michael0584

michael0584

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Not k5 related but there is such a wealth of knowledge here I thought I'd ask here first.
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, and today. Today was the only day 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, 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 ignition module on the distributor or the fuel pump, but not sure.
 
Figure out how to read the computer codes and you should easily find the problem. It is fuel injected so it is probably something like the EGR, MAP, or fuel pump/pressure regulator (or blocked fuel filter). But TEST them before you throw money, time, and effort away!

I had a 1990 Mitsubishi ... something full size and I discovered that many of them have a problem with the ECM failing. Cars like mine were being broken into and the ECM stolen since they where worth so much.
 
ecm is good and no codes, fuel filter has been changed. I'm gonna see if I can get a fuel pressure tester, I may also block off the vacuum line to the egr to see if that makes a difference.
 
Wait, you said it's been sitting for a year? You probably have bad gas or water in the gas. That's the first thing the Chevy manual says to check with TBI problems. I know there are additives you can put in the gas, but if it's been a year you should probably just drain the tank and put in new gas.

Generally the EGR only comes into play at high speeds, like 50 mph for the Chevy and I would expect about the same for the Mits. You can check it by putting a vacuum tester on it (if it's vacuum operated) and see if it holds vacuum.

You may also have cracked vacuums lines. Any car that sits for a long time will tend to rot. Pull off a few lines, wrap them around your finger. If you see any cracks replace the lines.

If that doesn't work search for my username and "TBI" and you will see lots of troubleshooting details I have posted about the Chevy TBI systems. However, you might want to sign up on a Mits forum as they can probably more quickly diagnose the issue which would save you time, money, and effort!
 
The car was cutting out back in 05. I put 5,000 miles on it in 05 with it cutting out, because it was fine short distances. When I got it out of th barn last week I dumped a bottle of heet, fuel injector cleaner, and octane booster in the tank and added 5 gallons of premium. I've now put 300 miles on it since last week. I really am leaning towards 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.
 
Well, get a fuel pressure tester and test how much PSI it has. That is probably a lot easier than swapping out the fuel pump if you don't need to.

Is it possible that the fuel pickup is stuck? Does the gas gauge register when you add gas?
 
Gas gauge does register and moves when gas is added. I need to get a fuel pressure gauge and test it, might be hard to see it though cause it only cuts out while driving.
 
I just went out and checked for vacuum leaks with carb cleaner. As far as I can tell no vacuum leaks. I also did not see a fuel pressure test port on the fuel rail.
 
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?
 
Ok, I think 40+ PSI is probably ok.

How are the plugs and wires? Bad wires could case that and is easy to check. Are they cracked/rotted?
 
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.
 
Yea, this thing had me cursing Mitsubishi for awhile. Now I'm growing to like it. Looks like I started driving just in time to as gas prices started creeping up as soon as I started driving it. I filled up today so we will have to see what kind of mileage I get.
 
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