Engine 2004 GT

[Jamespettet]

Hey guys! New to the forums. Been reading for awhile now though.

I’ve got an issue that I can’t seem to pinpoint. I hope this is the right place to post.

I’m a novice mechanic. My grandpa taught me the basics (plugs/wires/cap/oil change/etc) but I am in no way fully capable of deep repair, unfortunately. I would like to learn though.

My 40Th anniversary GT basically loses through put. Meaning that I’ll be pressing the throttle and one moment it’s fine and the next it feels like it has lost 50%+ effectiveness.

I’ve searched the forums for similar issues. Which led me to replace the COPs. The plugs were changed under 300 miles ago. I cleaned/piled the filter. The fuel pump is under 5000 miles old and it’s a performance pump.

It was extremely pronounced before I cleaned the filter and replaced the COPs. It has drastically improved but I feel that I’m only at about 75% of the power I had before this issue and the pedal still “goes away” at times.

Any help is appreciated. Thanks in advanced.

 

[Jamespettet]

An update /edit.

I cleaned the MAF today. And cleaned the electrical contacts of all of the intake sensors. I left it to dry for about an hour and notice zero change.

This happens in every gear. I’ve done a fuel treatment along with everything listed above. Still having issues with jogged acceleration.

Please advise. Thank you.

 

[wmburns]

Do you have an ODB2 scanner? Do you really want to fix this? If so, start by reviewing the following links.

Howto perform charging system voltage drop test
https://www.stangnet.com/mustang-fo...perform-charging-system-voltage-drop-test.56/

ForScan ODB2 scanner w ELM327 USB
https://www.stangnet.com/mustang-forums/resources/forscan-odb2-scanner-w-elm327-usb.57/

What is likely the best method to solve this problem is to figure out WHAT is changing when the problem occurs. For example:

• does the fuel pressure change?
• does the VPWR voltage change?
• does the MAF flow rate change?
• does the timing advance change?
• Does the EGR flow change?
• do any other sensors such as IAT, ECT change?

While it's entirely possible to trouble shoot your car without an ODB2 scanner, consider that if trying to LEARN how to work on your car doesn't it make more sense to learn the modern way to do it? Besides just think of how much work it would be to answer all of the questions above using a set of back probes and a VOM. With an ODB2 scanner it's possible to answer the above questions and more in a matter of minutes.

The alternative is to guess at which "parts to change" and hoping to find the "fix" by happen stance or good guess.