I'm Am Considering Buying A 1985-1993 Mustang

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Not all of us know how to fix everything, but some of us know how to fix some things
with excellence!

Places to check out here on Stangnet:
http://www.stangnet.com/mustang-forums/threads/technical-thread-how-to-index.808661/ How to do it tips for some of the most common problems and upgrades for 5.0 Fox body Mustangs.
http://www.stangnet.com/mustang-forums/threads/the-official-progress-threads-thread.761371/ the collection of build/progress threads from Stangnet members. You get to find ideas and clues to what works well and what doesn’t.
http://www.stangnet.com/mustang-forums/resources/ Has tech tips for common problems on Mustangs.

If you are in California or some other state with strict emissions laws, part of the deal should be that the owner takes the car and has it emissions tested. If it passes, you buy the car and pay for the emissions test cost, if any. If it does not pass, walk away from the deal. For a mechanically inexperienced owner, emissions related problems can be difficult and expensive to fix. Avoid any car that was originally EFI and has been converted to carb like the plague. That's often a clue to the fact the previous owner had problems and the resulting hack job has MORE problems.

Keep in mind that states with strict emissions laws may make the go faster goals more difficult to reach. Some parts are OK to replace with aftermarket parts and others aren't. Check carefully before you get out your wallet and buy something you can't use in the area where you live.


If you want to do the fix up & power up thing, make sure that you have some other form of reliable daily driver. That way the stang can sit while your wallet and hands take a rest from the last project that didn't quite get finished on that 3 day weekend. Things always cost more and take longer the first time you do them. Having some other working vehicle makes life easier since it isn't the big crush to get it running for the Monday morning drive to work or class.

Plan on spending some money on tools it you don't already have them. The stang has both metric and American fasteners, so you really need two sets of wrenches. A timing light, digital voltmeter, vacuum gauge, compression tester, fuel pressure test gauge and fuel line coupler tools are some of the test & tuning tools you'll need. Visit the pawn shops and sometimes you can find a deal on tools & test equipment if you stick to well known name brands.

A sheltered work area is almost a must, someplace that you can leave the car in pieces without upsetting anyone. Some guys here have changed a transmission in the parking lot of their apartment in a rainstorm, but they will tell you it wasn't fun. Depending on where you live, a warm dry garage is a nice place to do the winter projects that stangs tend to become.

EFI (Electronic Fuel Injection) Computer - every stang after 85 has or had one: don't let it intimidate you. The computer based EFI systems are not hard to fix and most of the time they tell you what's wrong with the engine. Here's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by James Probst: ISBN 0-8376-0301-3.

It's about $35-$45 from Borders.com see http://www.amazon.com/ . Select books and then select search. Use the ISBN number (without dashes or spaces) to do a search

Use the ISBN number and your local library can get you a loaner copy for free. Only thing is you are limited to keeping the book for two weeks. It is very good, and I found it to be very helpful.

For lots of great ideas and tech notes on upgrades and repairs, be sure to check
out http://forums.stangnet.com/showthread.php?t=643651 “Useful Technical Thread Index” sticky at the top of the 5.0 Tech forum.

Things to avoid at all cost: EFI to carb conversions. It is too easy to become a victim of the previous owner's efforts. Some states will not title or issue license plates to cars that have been converted from EFI to carb. Some of the motivation of my negative comments about EFI to carb has to do with the quality of electrical workmanship.

Things that break often:
T5 5 speed manual transmission (syncros go bad, mostly 3rd gear)
TFI Module (Thin Film Ignition module - mounts on the distributor)
Electric door locks (see the link in my sig for a cheap & easy fix)
O2 sensors(oxygen sensors) They are good for about 60,000 miles and start to go down hill after that.
TPS Sensor (Throttle Position Sensor) causes flaky problems with idle & acceleration.
Fog lights They overheat the wiring and cause the headlights to flicker. The fix is cheap and simple if you can do electrical stuff.
Harmonic Balancer – they separate between the hub and outer ring. A harmonic balancer puller is a must have to change it. You can rent or borrow a puller from most of the larger auto parts stores.

Things that are very durable: Engine - as long as it hasn't been abused, it will run good for 150,000-200,000 miles without an overhaul
Rear axle - other than an occasional case of worn clutches in the traction lock, they almost never have problems.
Computer - believe it or not, the computers seldom have problems of their own. Most of the problems are with the sensors and the wiring.
Suspension – the front and rear suspension has very few problems if the car hasn’t been wrecked or seen a lot of drag strip runs. The drag strip runs tend to distort and tear the mount points for the rear axle control arms. Revving the engine up to 4000 RPM and dumping the clutch with slicks or drag radials tends to break things.

Things that don’t break often but are hard to fix:
Water pump mount bolts – they corrode and shear off when you try to change the water pump.
Rear oil seal on the engine – lots of parts to remove to get to a $20 seal.
Power steering pump – the pumps are noisy and the pulley requires some special tools to remove and install. If you have the tools, they are easy to do. Again, the larger auto parts stores will rent or loan the tools for the pulley.
Power Steering rack - it is hard to get the toe in set so that you can drive the car to the shop to get it properly aligned.
Starter – the top bolt is hard to get a socket on if you don’t have the right combination of socket, universal joint and extensions.

Everything considered, 5.0 Mustangs are not hard to work on. They just require some patience and though before you get started.

I just recently bought a 90 coupe, 5.0 5 speed. I've driven it every day 50 miles round trip without issues. With that said, I've put a lot of work into making it reliable and still work on it daily to continue improving. Most of it is basic maintenance that the previous owner overlooked, but regardless, be prepared to turn wrenches frequently.

Generally speaking, I would not recommend a fox body mustang for reliability. I would, however, recommend one for fun.

Food for thought, a fox which is even remotely reliable is going to cost you $5k+. I recently sold a very reliable 2006 GT for 6995. There's a day and night difference in reliability there.

hoopty5.0 said:

I just recently bought a 90 coupe, 5.0 5 speed. I've driven it every day 50 miles round trip without issues. With that said, I've put a lot of work into making it reliable and still work on it daily to continue improving. Most of it is basic maintenance that the previous owner overlooked, but regardless, be prepared to turn wrenches frequently.

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The issues are coming.

Sharad said:

Generally speaking, I would not recommend a fox body mustang for reliability. I would, however, recommend one for fun.

Food for thought, a fox which is even remotely reliable is going to cost you $5k+. I recently sold a very reliable 2006 GT for 6995. There's a day and night difference in reliability there.

Click to expand...

Plus not as slow out of the box.

90lxwhite said:

Plus not as slow out of the box.

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Suspension too.

85rkyboby said:

Suspension too.

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All around better vehicle really.

I agree with much of what is said. A Fox Daily Driver is not for the uninspired or those not willing to get their hands dirty. These are 20+ year old cars that were marketed to young people and for the most part have been run hard.

Unless you are willing to pay up for one, you are going to run into many beaters. The key things to avoid are rust, torn torque boxes, and nutswinger hacked up wiring and engines. I looked for 6 months and over 40 cars before finding a 2 owner, low mile, bone stock car. Paid $5000 for it and have probably put that much into it since.

If you are a good mechanic I'd say if its your preference go for it. I have about 9,000 in my 83 with just over 300rwhp. But if you have to pay someone you might think about a newer Mustang.....one thing I'd look at close would be the front end make sure all of it is tight. Or simply ask the guy if you can have a mechanic shop look at it, most shops will check it out for free if they know you are buying it. Then they will say ya good car or run away. Good luck

IMO spend the money up front by going with an 89-93 with a manual trans.
Saves you the trouble of converting to mass air.
You also won't have to convert the car to a stick when you figure out without it, the car just isn't that much fun or isn't that fast.
And you won't have to worry about the flat top pistons when you swap the cam and heads.
So a couple extra grand when you buy the car will save you 3 times that on the back end.

Hagerty marketplace has a beautiful 87 convertible up for auction right now. I believe there are either six or seven days left before that auction closes.