Progress Thread Giving an abandoned 88 GT project a new chance at life

• TPS sensor, replaced with a new one and set at .98 volts
• MAF, brand new
• Fuel Pressure Regulator, Brand new
• Timing, set at 12 deg (with the spout out)
• Distributor, Brand new LMR replacement
• TFI, Brand New
• Firing Order, checked and rechecked
• Spark Plug Wires, Ford Performance Black Wires
• Coil, Brand new also check with a different known good coil from a friend's car
• Factory Replacement Injectors, Brand New (Ignore GT40 Lower in the photo ended up taking off to restore)
• Alternator, Converted to 3G and checked the wiring
• Ignition Switch, Brand new

• When going uphill the car performs as normal if not a little down on power
• When going downhill the car surges and tries to buck if you press the gas at all
• When cruising on flat and level ground, if you let off the throttle at all the car surges and bucks at any RPM above 2500 (SEE VIDEO)
• Large Voltage Drops when free revving or shifting (SEE VIDEO)

• No AC/ Heat including the removal of the fuse to said system
• EGR Delete with block off plate
• The carbon Canister is missing but the solenoid has been blocked off
• Smog pump is installed but no lines are connected (The holes behind the heads have been blocked off
• No Cats (Aftermarket H Pipe w/o smog pump holes
• Intake has been redone and reseated with no leaks coolant or vacuum-wise (stock Foxbody intake)
• 4-cylinder gauge cluster
• Mini starter upgrade
• Exhaust Leak at headers (there are a few that I am chasing down)
• Aftermarket shorty equal-length headers

• 31 ORC EVP circuit below minimum voltage
• 85 O Canister Purge (CANP) circuit failure
• Code 11 On the Continuous Memory

jaketractor said:

Hello, my name is Jacob I am 20 years old, and am not new to Mustangs, but I am new to the Foxbody platform.
I found my Foxbody on Facebook marketplace last summer (early June). It is an original California GT but I believe that is where the originality ends.
It seems to have been manual swapped as the shifter bezel doesn't fit without trimming (SEE PHOTO) .
The previous owner also claims that the motor that is currently in the car came out of a 94/95 Mustang. The motor has been dressed with all of the original Foxbody accessory drive.
The car also had a Cobra computer(X3Z SEE PHOTO) in it when I bought it but had the factory injectors and no MAF installed. I was able to get it to turn over with a wrench when inspecting the car before purchase so I knew that I had a decent chance of getting it running.
The previous owner had recovered the car from his mechanic after the car had sat in pieces for about 6 months. He wasn't mechanically inclined enough to rebuild the car, this is why he wanted to sell it.
Once I got the car home I was able to get it to run very briefly with some starting fluid but I still had a long way to getting it running and driving.
I started by updating the MAF plug from the 88 California MAF to the 89-93 MAF plug to make it easier to find parts. I also had to re-run the TFI wiring as the mechanic had no idea how to do electrical work and it was too big a risk to keep moving without fixing the "twist and tape" wiring. I also had to order intake piping because there was none in the car when I purchased it. I also had to get a MAF housing which my buddy was nice enough to give me as he had an extra. With this work, I was able to get the car running a bit longer but the fuel pump decided to go out at this time. I replaced the fuel pump, fuel level sender, and fuel filter and cleaned and painted the tank since it was already out of the car. After getting it back in the car I was able to get the car to idle but it was idling very poorly because of the mismatched computer and injectors. I ordered an A9L and this was able to get the car idling better. Now that the car was running better I realized I had a vacuum leak. I chased it for about 2 weeks until I finally found the leak from the unused AC vacuum system. The car was now ready for its maiden voyage around the block. It still ran like crap... I have an issue that I still cannot find.
I have replaced/checked

• TPS sensor, replaced with a new one and set at .98 volts
• MAF, brand new
• Fuel Pressure Regulator, Brand new
• Timing, set at 12 deg (with the spout out)
• Distributor, Brand new LMR replacement
• TFI, Brand New
• Firing Order, checked and rechecked
• Spark Plug Wires, Ford Performance Black Wires
• Coil, Brand new also check with a different known good coil from a friend's car
• Factory Replacement Injectors, Brand New (Ignore GT40 Lower in the photo ended up taking off to restore)
• Alternator, Converted to 3G and checked the wiring
• Ignition Switch, Brand new

The car is consistently cutting out at 2500 rpm when sitting in neutral and at a stop.
The car is bucking and kicking at seemingly random RPMs when driving.

• When going uphill the car performs as normal if not a little down on power
• When going downhill the car surges and tries to buck if you press the gas at all
• When cruising on flat and level ground, if you let off the throttle at all the car surges and bucks at any RPM above 2500 (SEE VIDEO)
• Large Voltage Drops when free revving or shifting (SEE VIDEO)

I

I have some issues with the car that I am unsure if it affects the situation that I am currently having, but I am going to list them in case they are a variable.

• No AC/ Heat including the removal of the fuse to said system
• EGR Delete with block off plate
• The carbon Canister is missing but the solenoid has been blocked off
• Smog pump is installed but no lines are connected (The holes behind the heads have been blocked off
• No Cats (Aftermarket H Pipe w/o smog pump holes
• Intake has been redone and reseated with no leaks coolant or vacuum-wise (stock Foxbody intake)
• 4-cylinder gauge cluster
• Mini starter upgrade
• Exhaust Leak at headers (there are a few that I am chasing down)
• Aftermarket shorty equal-length headers

I ran the codes and only received a few (KOEO)

• 31 ORC EVP circuit below minimum voltage
• 85 O Canister Purge (CANP) circuit failure
• Code 11 On the Continuous Memory

I have attached photos of how I got the car, the previous owner's handy work, the shifter location, and some videos of the issue I am facing at the moment.
Any advice would be greatly appreciated. Thank you guys for being so welcoming. I really love this Foxbody platform and I would love to get to enjoy this car.

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Noobz347 said:

After that, I would highly recommend this:

clicky clicky

Thread 'Help me create the "Surging Idle Checklist"'

Apr 10, 2005

Updated 05 July 2022 to add rough idle when cold and smooth idle when up to normal operating temperature. See the EGR tech information, section #15 for more help.

Many of you are familiar with the "Cranks OK, but No Start Checklist for Fuel Injected Mustangs" checklist and the No Crank Checklist. They are very effective in finding and eliminating the problems by use of a systematic process that checks and eliminates possible causes. This idle problem checklist will use the same troubleshooting strategy and methodology.

By the term surging idle, I mean an idle that...

• jrichker
• 1986 1993 86-93 check engine light code 67 cranks ok dump codes eec-iv mustang no start
• Replies: 575
• Forum: Fox 5.0 Mustang Tech

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AeroCoupe said:

Mechanically the transmission appears to be sitting way too high. Take a look at the transmission crossmember and it should look like this:



It may be failing motor mounts but I would suspect from the quality of the swap they hosed the transmission install. If you can get the transmission down like it is supposed to be you will need to get another shifter boot and cut the hold a little bigger to clear the Pro 5.0 shifter (same one I have). This will keep the exhaust fumes and heat out of the interior of the car.

https://lmr.com/item/LRS-7277E/79-04-Mustang-Lower-Shift-Boot-With-Metal-Ring

A new shifter bezel would clean things up as they notched the one in the car which should not have to happen. Will also need a shifter boot. Both can be had at LMR or the like.

Also, where the mechanical engine temperature gauge is connected needs to be removed. This is where the ECT (engine coolant temperature) sensor goes and it critical to the ECU controlling the engine. The wiring appears to be there so you would just need to buy the ECT sensor and install it. YouTube video here:

View: https://www.youtube.com/watch?v=UJw5mLZRMEg


There should be a braided wire grounded to the firewall and I believe the driver side cylinder head. My car does not have one as I built all my cables so I did it a little differently but you need a ground from the battery to the frame, frame to the block, and it helps to have one from the firewall to the engine.

An orange wire from the injector harness should be grounded on the back intake bolt on the passenger side. Its #19 in this diagram:



Also, make sure the ECU ground behind the battery is in good shape:



This is just what I can see from the pictures you have posted. Someone had no clue as to what they were doing before you got this car so be patient and work the problems as they present themselves.

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