Engine 96 gt hesitation on acceleration

[ja96gt]

hi
new here, I have 96 gt that I owned since 01, this year it's got a bad hesitation on hard acceleration
I cleared the codes which were p0125, p1443, which I changed the ect, evap purge valve and sensor and vac lines, no check engine light now.

I also changed the fuel filter, cleaned the maf, new gas cap, ran seafoam through it.

the engine idles fine and runs strong just has the issue under load.

the car has 108k miles, I am thinking it might be the intake manifold? still has the original plastic one

thanks for any ideas!

 

[ja96gt]

anyone out there?

 

[wmburns]

Do you have an ODB2 scanner? If so, what are the LTFT's between idle and 2000 RPM's? Often an intake leak with have large positive LTFT's at idle that decrease at 2000 RPM's.

The other way I prefer to test for intake leaks is to use a propane wand to "probe" around joints looking to see if the RPM's change when the propane is ingested. I'm not a fan of spraying carb/choke cleaner to look for leaks (to each his own).

What have you done to rule out a problem with:

• The spark plug wires
• the spark plugs
• the fuel injectors
• the fuel pressure
• Base engine

Have you monitored fuel pressure or LTFT's during pulls? Often ignition related issues will become worse as engine load increases.

Have you cross checked the PCM reported ECT value against a reading with an infrared thermometer scanner?

What have you done to rule out a bad alternator diode?

What is the intake vacuum at idle and under load? What are the results of a compression test?

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P0125 - Insufficient Coolant Temperature For Closed Loop Fuel Control​ Indicates the ECT or CHT sensor has not achieved the required engine operating temperature level within a specified amount of time after starting engine​ Insufficient warm up time Low engine coolant level Leaking or stuck open thermostat Malfunctioning ECT sensor Malfunctioning CHT sensor