Just bought my first Mark VIII


LVC Member
Jul 16, 2014
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Well I found a good deal on a 95 Mark that I couldn't pass up. 137k Black on black, a J-modded transmission with Merc V, Xpipe to bullet mufflers, already converted to T-bird springs, K&N and some sort of stock computer installed that is an upgrade? All the electronics work and the interior is in pretty good shape for it's age. I've had it for about a month and love it so far, such an underrated car. Now for a few questions. Is there a way to turn off the " check air ride system" when you start the car? it's quite annoying. The temp gauge in the car seems to fluctuate quite a bit, most of the time it's very low in the "normal" range on the gauge but occasionally wont go into the "normal" range and occasionally will sit between the R and M in "normal" range. The fan functions properly and there is no pattern as to when and why it changes during normal or spirited driving. Any ideas? On my way home from buying the car a CEL popped on then went away about 30 seconds later, it has done the 3 additonal times while I've owned it but always goes away shortly after. There is no change in performance or driveability when it comes on and again there is no pattern as to when and why it pops on during normal or spirited driving. Ideas? Front rotors need to be replaced as they are warped, I know this is very common for the Mark, and from what I've read most people just replace them with cheap rotors and change more often. Are there any aftermarket rotors that would help against warping? I don't want to swap to Cobras, just a good stock diameter replacement that may net me some braking performance and have longevity. Last thing, sorry for the long post. The transmission under moderate acceleration shifts great, under hard acceleration it shifts firm and chirps into second pretty good, but under normal stoplight to stoplight it seems to shift way too low in RPM, very sluggish. Is this a common problem? If you took the time to read all this i appreciate it, I'm very excited to fix this Mark up, just looking for some advise from the people who know them oh so well. Thanks, Ben.
I'll answer the last question since it's late and my brain is overly warped at the moment. Mark VIIIs are notorious for shifting early and racing to get to overdrive if you keep it on in town. It's supposed to maximize fuel economy apparently. I got a tune and put an end to that ASAP! I hated it.

Welcome and congrats on the BoB!!! Woohoo. Mark VIIIs get under your skin big time. Be prepared... :)
First off, welcome to the Mark crowd and to the board, it sounds to me like you have a fantastic example, these cars are killer in Black/black. Though they are all special in their own way, really. : D

I'm going to go ahead and be entirely honest on the first one, and say that I cannot be sure about what kind of bypass you need to do to disable the check air ride message. I remember reading about how it was done once, but I can't recall, and since my '96 is still on air, I guess it didn't seem worth retaining at the time, lol. But I am sure someone with a Mark on coils will chime in here very shortly and put you right.

As for your temp gauge, gen I gauges are kind of spotty. I've read reports and seen cases where two cars operating at the same coolant temp show distinct differences at the gauge. Your temp sender might have a few spooks, but in reality, as long as your system is up to snuff, it's been properly burped, and the fan is operating as it should, I personally wouldn't lose too much sleep over it.

As far as the CEL goes, a host of things could be at work there, O2 sensors, IMRC (less likely, but possible), EGR, etc. Etc. The only way you will really know for sure is to get your hands on a decent OBDI scan tool, and a '95 shop manual while you're at it. They are pretty important to have if you plan on keeping her for a while, believe me.

As far as the brakes go, I've got a set of Raybestos rotors on the front, and they have yet to warp after ~10k miles, maybe I'm just lucky, but then I don't necessarily jam them to a halt at the last second coming off of the interstate from 85 either. Previously when my father owned the car, he had installed a set of EBC drilled/slotted rotors on the front, and I don't know if it was the build quality or what, but those turned into lasagna in no time flat. Seems like half of it has to do with your driving style, and the other half the quality of the part you are installing.

And as Hot*Mk8 said, the 4R70W in these is just that way. I'm a long way from being able to afford any kind of transmission goodies, so a quick fix that I have been employing for any driving at or under 40mph is turning the O/D off. Of course, at 25mph or so, she still likes to lope around at 1000 rpm, but at least at 35-40mph, it's a more manageable 1500 or so. The silver lining I suppose is the 4.6 DOHC's ample production of torques, lol.

So yeah! Enjoy her as I'm sure you will, and good luck to you both. If you take care of her, she will take care of you. An "understanding", if you will. ;p
For the check airride message, there's a module behind the dash. You have to let the glovebox hang out of the dash, and it is in the upper left mounted to the dash frame at the "curve" of the dash. Flat module w/ 2 plugs. One on each side. You have to cut one of the wires. As for which wire to cut, I dont remember.
The temp gauge in a gen 1 responds more like an actual gauge and fluctuates with the actual temperature of the engine. The electric fan ON point is the bottom of the R and the OFF point is the M. If the car is in motion with more airflow past the radiator the temp can be lower. This is normal. In a gen 2 the temp gauge is more like an idiot light, the needle will go to the middle and stay there so customers don't call the dealership with questions about the running temperature of their car.

I would recommend buying a FORD OBD 1 code reader off ebay for $20 bucks or less. It's a rather simple device. You might have a miss fire but the code reader will tell you for sure.

I have Power stop rotors and Power stop ceramic brake pads. They work better then stock replacement. You can check them out on Summitracing.com

Like Hot*MK8 said you can get a computer tune to readjust your shift points + other things. In your case you would get a chip because you're OBD 1. Before you order you have to identify what computer you have now since you say it's been changed. You might have a 93 computer... that's supposed to be the 'hot one'.
I appreciate all the responses. I'm gonna look into getting a custom chip as I've heard they do wonders on these cars. Iv'e done a little research and it seems that BOC is who i should go to? What would be the total cost for say a 2/3 program chip? I'm gonna try to search about the wire to cut fix the air ride message as well. Has anyone used stoptech cryo rotors? i believe they're supposed to fight warpage. As far as the scanner goes, would i even be able to pull the code?, it happens so quickly and as soon as you turn the car off its gone. the one thing that really urks me about the car, as far as looks, is the stock wheels, they sit in way too far and aren't very appealing haha. I don't really want to do the hub swap, so I've decided i want to get some black speedstars. Used ones would be awesome, although hard to come by, so if anyone has any leads I'd appreciate it.
I have a BOC Lonnie tune and recommend it. I don't know what a 2/3 program chip is but check out blueovalchips.com for prices. I also recommend you call Lonnie at least a month before you want the chip because he is very busy and can take a while.

Yes you can pull the code. It would be a stored code that can be retrieved with the code reader
,Welcome to LVC I have a 95 I got 14 years ago, and it has the same rotors on it. At one time it pulsed like a warped rotor. I cleaned them really good and they act like new. Just did the fronts on my 94, and there much better. Still have to do the rears. I have 5 MK VIII's, and the 95 has the best brakes out of all of them. If the rotors are shiney, and glazed, try cleaning them with corase emery cloth, then fine emery. BUT IF YOUR GOING Hot ROD GET all that big stuff $$$$. Oh yea, my 95 has 122K miles on it, and it stops great. Enjoy the site, lots of good info TONYyyy
So I figured out that you can just use a jumper wire and pull codes. Here's what I got, 172, 175, 176, 189, 524, and 543.

Sounds like I've got some some bad O2 sensors, and possibly faulty fuel pump? Any suggestions from those of you that have dealt with any of these codes?

Also, I did notice that the gasket between the air intake tube and the throttle body is completely shredded which is most likely causing a big vaccuum leak but i have not been able to track one down.

172 - o2 Sensor sensor circuit indicates system lean (right side)
175 - Fuel system at adaptive limit, o2 Sensor unable to switch(left side, (Bank No. 2))
176 - o2 Sensor circuit indicates system lean (left side)
189 - Left side still lean, at richest adaptive limit, during part throttle
524 - When the PCM commanded the fuel pump on, voltage was not detected on FPM
543 - When the PCM commanded the fuel pump on, voltage was not detected on FPM
i would think you have either a bad O2 sensor or a pre sensor exhaust leak on that side.

maybe vac leak, but i would expect to see both banks lean with most vac leaks.
Ok, I fixed a small Vac line that was broken, and got the intake tube gasket I needed. Cleared the codes, 172 175 and 176 came back. Would replacing the O2 sensors be my next logical thing to replace? Ive done some research about these codes but i haven't found a thread that says a solution. Could It be clogged cats? The exhaust smells pretty bad if im hard on the gas and 3rd cat is already gone. And I'm pretty positive that there are no exhaust leaks.
It definitely wouldn't hurt to change them. They are no picnic though. Possibly at least one is bad. It's also quite possible that the engine runs lean like the o2 sensors say. Maybe your fuel pump is weak? That's another job that isn't a walk in the park

The o2 sensor unable to switch is probably the bad one
Before you get the custom chip it's probably a good idea to change the fuel pump anyway especially if it still has the original pump with 137k
I'm going on vacation next week so I haven't bought new o2's or a fuel pump because I've been saving money for said vacation (I'm doing both these things as soon as i get back. However, I found a good deal on a used chip from a car with about the same mods as mine and I couldn't pass it up. Now here's where my questions arise, it still throws 136 and 172, which I expected, but it started throwing new codes. 511 obviously, 117 which is for the ECT, and 652 which states modulated converter clutch control solenoid circuit output error. The CEL also comes on WAY more often (going down the highway is like a light show) and also WAY sooner after I clear the codes. Iv'e noticed now that it's mostly when cruising 55+. First off, I'm kind've confused on how the CEL works, I've never owned an OBD1 car. When the CEL illuminates is it saying the car is currently malfunctioning at that point? Or is it a constant problem? It seems as if when its on my gas mileage starts dropping instantly then it goes off and it starts picking back up. BTW the average mileage dropped from about 16 to around 14 (which is uncommon with a chip) upon install and this is with no heavy foot. , I feel as if the car has lost a bit of power, is this just because of the possibly faulty O2's and fuel pump compounding with a leaner A/F ratio from the chip? The chip was made for a car with a j-mod and it actually feels great, slightly firmer than with the W3Z2 that was in the car. Could something about the tune for that be causing the converter code? Lastly, with the program the cooling fan is supposed to come on at a lower temp, which I assume involves the ECT, could this be causing that CEL? I know that with OBDII fords when you have a check engine light it stays on until the problem is fixed, and if you have a CEL the ECU kind've goes into a set dummy mode, is this what happens with OBDI fords for stored codes? I'm slightly confused, and if any of these questions are stupid I'm sorry, just need a little direction and any help would be awesome.
Remove the chip, and clear the system and see if you still have CEL's. Used chips may not be the best to invest in as all cars have their own idiosyncrasies. Old sensors and a worn out fuel pump don't help maximize performance either. Be sure you also install a new fuel filter when you change out the pump.
Ok, so about a week ago I finally got around to replacing the o2 sensors, what a PITA! I decided to drop the exhaust (which by the way is one solid piece from the manifolds back) but luckily I did, turns out the drivers side converter had broken up. I ended up doing the unmentionable to both converters, mainly because a stock replacement is astronomically priced. Down the road I'll get some put in down stream. Also replaced the fuel filter. Bolted everything back up, cranked her up, went for a drive. WOW, like a whole new vehicle! After a week of the daily commutes which involves no highway and alot of stop and go I'm sitting at 19.5 average mpg. Runs so much smoother, and picked up all the power I had lost with a faulty converter and faulty O2's. Plus NO CEL's. Couldn't be happier. Got some fresh 245 50 16 rubber I'm bought to throw on with a fresh alignment. All it needs is some paint and I'll be set.

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