2.4 efi engine surging

[mylittleshitty]

Hello everyone, Let me start off i'm new to the site and diggin it cool to see a forums for our truck's. I own a 93 MMM with 2.4 efi starts up fine idles good but when start to take off the engine will hesitate and surge from 800-2000RPM. I have to stomp the gas pedal to the floor repeatedly then it levels out and runs ok. It does this at stoplights and while driving very embarrassing at intersections.Have changed distributor cap,rotor,wires,plugs,fuel filter,air filter, and battery.

I'm at wits with this thing cant figure out the issue.

[pennyman1]

Sounds like a vacuum leak - check the intake, throttle body, and vacuum lines by spraying with carb cleaner or use an unlit propane torch to see if the motor speed changes. If this is all good - it could be that the computer needs recapped.

[DroppedMitsu]

also make sure the throttle cable isnt too tight or hanging up on anything, my friend was having this problem and his cable was a little too tight.

[LSR Mike]

This could actually be a Water Temp Sensor that feeds the ECU, it's different than the one for the gauge. causes the same problem, the ECU thinks the motor is up to temp.

[mylittleshitty]

This could actually be a Water Temp Sensor that feeds the ECU, it's different than the one for the gauge. causes the same problem, the ECU thinks the motor is up to temp.

That sounds about right does it on initial startup cold, and sometimes in town. Where is that temp sensor located?

[blindeyed]

Coolant Temperature Sensor is located here:



Directly on top of the coolant neck housing, with a 2 pin connector that is shaped like a "T". It's about a $15 part, so worst comes to worst if it doesn't work, you did some cheap preventive maintenance. If that doesn't solve your problem though, next thing I would look in to is your Throttle Position Sensor.

[mylittleshitty]

Thankyou everyone very much for all your helpful advise, this issue has been a pain in my ass since i bought the truck back in summer of 07. I ordered the ecm temp sensor today from autozone should be in tomarrow. Hey blindeyed was searching on youtube about this issue and came across your video's I see you're on LS1TECH.com added you as a friend i'm LT1_T56.

[mylittleshitty]

ok finnaly got time to get back with yall on my issue, replaced the sensor and the problem is still there if not worse now takes 1-2 seconds longer for the truck to start now. This only happens in open loop once closed problem goes away. Does the ecm read off the temp sensor as well as the oxygen sensor in open loop? maybe the o2 sensor isn't sending info that it heated up.

[Rahtid]

I had the same issue,my truck would lose power every time i went into 2nd gear or 1st if i gave it more than a 1/4 throttle. My problem was a bad tps sensor