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View Full Version : 1990 2.4l mighty max bogs down on accelaration



killswitch
04-30-2015, 02:40 PM
the truck runs fine when the engines cold but when the engine is warmed up it bogs down past 20% throttle and when in neutral it surges at any amount of throttle

pennyman1
05-02-2015, 12:43 PM
you have a vacuum leak - tighten all the intake bolts and throttle body bolts. Spray down all the vacuum lines and intake area with carb cleaner - when the rpms change, you found the leak.

killswitch
05-02-2015, 02:27 PM
than you for the response much appreciated

killswitch
05-03-2015, 07:06 AM
ok well I went through all the vacuum lines, replaced the ones that where bad then sprayed every nook and cranny in the engine bay and there was no change in rpms, changed the fuel filter and changed the mass airflow sensor, but it still bogs down. I looked up how to read the engine codes and it is throwing 14 engine position sensor and 15 throttle position sensor would that cause it to bog down

killswitch
05-03-2015, 08:00 AM
another thing I should mention is it only bogs down when the check engine light is on, the check engine light comes on and off at random, when the light is off it will run fine and I can accelerate but when it comes on I have to wait till it gets below 35 mph before I can accelerate again but the light will still be on so I can only accelerate 20% throttle until the light goes off

killswitch
05-03-2015, 08:05 AM
I am wondering if the ecm is bad even though its not throwing the code for a bad ecm

killswitch
05-03-2015, 10:36 AM
how do you adjust the tps sensor and how do you check if the tps is bad

killswitch
05-03-2015, 01:22 PM
ok I changed the tps and its still bogging down

pennyman1
05-03-2015, 05:09 PM
the caps in the ecm are bad then - there is a thread on here on what they are and how to replace them.

killswitch
05-04-2015, 05:57 AM
ok again thank you and much appreciated

1mxdude
07-24-2015, 01:03 PM
I have a 1992 that is doing the same exact thing! I stole the truck for the money even though it didn't run. P.o. said bc of a fuel issue. He also had so much b.s. aftermarket gauges, msd blaster coil, I mean the list goes on. So I started by pulling an entire wire harness from pick and pull, along with all factory coil, gauges and ecm. Replaced all that. Truck has aluminum fuel cell with bad fuel pump. Replaced with working in line elec. Pump.,truck was only turning over but not Starting. Pulled timing cover and cam gear was off by two teeth the best I could tell. Tore it all down, got it all lined up,installed New plugs. It came to life! Truck runs fine untill the. Check engine light comes on and it is the same exact thing that you are saying 150%. It will sit an idle all day long though. Any updates on yours? Please keep me informed

Merrill
07-24-2015, 02:50 PM
To confirm - did you get the exact same codes as well, or is it just the exact same problem?