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My colt randomly has hesitation problems when accelerating, has no balls going up hills and this is causing bad gas mileage. Weird thing is its completely random. So days it will drive fine, other days it drives awful, some days in drives ok. I replaced the fuel pump, tried a different ecu, tried a different MAS, installed a new throttle position sensor, new fuel filter, checked the timing, all this and still runs the same. Also there is no check engine light. I'm thinking maybe a Knock sensor but I don't even think the engine has one. Any help would be nice, thank you.

did u check the timing belt.. 1 tooth off will cause intermittent issues..


Steve

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Steve 89 colt 2.3 stroker stock top end. evo3@20 psi 13.489@99.30mph 3/10 2012
On drag radials.auto trans.launching @ 5 psi and no traction thru 2nd.

Yep, checked the timing. Also probably unrelated, but shes leaking a good amount of oil.

It's a Mitsubishi so get used to that.

Have you done the basics like plugs, wires, distributor cap, rotor button? I am assuming this is a 1.5 sohc GT car correct, if so no knock sensor.

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Joey Santiago

2003 Lancer Evolution 57k original miles
1992 Montero LS
1989 Plymouth Colt GT (AWD project)
1989 Dodge Colt GT

Yes, sorry I forgot to mention that before, but I have replaced the wires, cap, and rotor. I haven't replaced the plugs yet because they look fine and aren't that old. Maybe I'll do that next. Also, yes. Its 1.5 sohc, thanks for confirming that it doesn't have a knock sensor. If its not the plugs, does anyone think it might be the distributor its self? I'm running out of options.

OBD1 especially in Mitsubishi's will run just awful without a CEL. Next area's I would address would be the O2 sensor and the coolant temp sensor. For sanities sake I would also do a health check on the engine and do a compression check and a leak down test.

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Joey Santiago

2003 Lancer Evolution 57k original miles
1992 Montero LS
1989 Plymouth Colt GT (AWD project)
1989 Dodge Colt GT

Turned out it was just the ECU. Hard to believe both ecus I used before had the exact same problem. I bought a refurbished 1.8l ECU, paired it with bigger injectors, and maf sensor and it's running well now

ECU's of this era are all due for rebuild if the capacitors are original or weren't caught in time to prevent other damages to the board that creep in after the fact - ie acid on traces/components.

Glad to hear you caught it!

I just got same problem with my base mirage 1989 1.5l

It missfired from dead stop. It would be stuck at 1500rpms.once broke thru it pulled like bat out of hell till redline.
But slowing down and rpms fall to idle but still rolling, it shuddered like a missfire and again after 3to5 seconds of that accelerate just fine.

But in the morning when really cold i noticed rpm guage showing 0rpms and twitch a bit. Reving up (by ear maybe 4000rpms) it barely showed 1000rpms. Also miss.

I changed the distributor and no change.

I was thinking About ecu but i don't have a spare one.

Remove the ECU and inspect for any signs of original capacitors being still in place. Search DSM ECU capacitor problem/pictures and you will see the signs of bloated and or leaking acids from the caps. This eats traces and causes general bits of mayhem to ECU operation. Easily fixed if the damage is not extensive and requires 3-4 capacitors and some times with a proper solder tech. Like $5 in parts plus their time.