Hello all. My name is Tony and I live in central Virginia just Southwest of Charlottesville. I am posting here because I can't find anything in central Virginia, and I grew up in York County, spent a good 30 years between the tidewater and peninsula.

I inherited my grandparents cars this year after my grandfather passed away. I am quickly becoming overwhelmed financially trying to get the cars back to reliable and fun condition. One of the cars is an 89 Cougar XR7 SC - cousin of the Thunderbird SC. Same engine and trans as far as I'm aware.

This car has been garage kept since day 1, and after my grandmother passed in 2015 my grandfather didn't ever drive it, just started it in the garage and let it run for a while, then shut it off. This process was once a week on average for 3+ years. It ran rough for at least those 3 years while it idled in the garage. But now that I have it, I have had it in 2 shops, replaced numerous parts to the sum of about $1100 doing most of it myself.. no luck. The car idles horribly. It runs fine when you first start it, nice and smooth, rpms where they should be, etc.. then as soon as it warms a little, 10-20 seconds, the idle drops to around 650-700 and it runs very rough. Has great pedal response, but when you let off the pedal the rpms drop and it acts like it was to shut off then immediately kicks back up to 650ish rpms and resumes running rough.

Driving at 45-60 mph it seems smooth, unless the AC is on, then it seems to buck a little when the compressor cycles (low freon, but has the silly Ford only low pressure adapter and no shop around has a way to charge it, or a conversion for it. But I don't usually run the AC anyway so I am not worried about this right now. Only the rough idling - to the point where you can watch the engine "rock" a little under the hood.

I have replaced so much as suggested. There is NO check engine light. It only came on once or twice under WOT from a stop, then as soon as I let off the gas pedal it was gone. Nobody has been able to pull any codes, or find anything wrong electrically, no vacuum leaks, supercharger piping resealed with correct teflon gaskets, etc.

There is a new MAF sensor, coil pack, plugs, plug wires, cam position sensor, thermostat, engine coolant temp sensor, radiator, DIS module, etc. I have spark from all positions on coil pack, spark to all plugs, proper motorcraft plugs and wires, I have tested the radiator for exhaust gases with a good block tester, no coolant and no sweet smell from exhaust pipes (no smoke from pipes, but it does smell a little rich on initial start), I have the correct fuel pressure that I am supposed to have at idle. I have run 2 tanks of quality premium gas through the car, one with Seafoam (first shop said bad gas from sitting so long), second tank used Lucas fuel injector cleaner. I have checked the injectors for function with a Quick Fuel Injector Tester (pulses and beeps with the motion of each injector).

I am just at a loss with this car and I do not want it to sit and rot in my driveway. I would like to get this car running again but there just doesn't seem to be anyone out here who understands these engines, and I am at the point where I am willing to pay to have it hauled to a shop that knows these cars if I can ever find one. I have spent about half the cost of an engine replacing parts that haven't fixed the problem.

As a side note, may not be related, when you step on the pedal to make the car downshift and go, it downshifts after about 3/4 throttle, and only lasts a second or 2 before it shifts back into regular gear. It will not maintain "passing gear" at all.. just goes right back to regular drive (3rd I believe), if you maintain 3/4 throttle or more, this is when the check engine light has come on twice.. but immediately goes away as soon as you let off the pedal. And I tried to check the timing with my Innova Pro, but when I connect to the #1 wire, the light is very erratic and not a constant flash. It "walks" all over the place, the timing mark goes between 0 and off the marks completely on the advanced side. But when I connect my inline spark tester, the flash is fast and constant just as with the other 5.

I am an OBDII and old school carburetor mechanic. I know nothing about OBDI to the point where I refused to buy project cars because they were OBDI, I only have this car because I inherited it, and I am headstrong about getting it fixed for my grandmothers memory. I feel like I am so frustrated with it that I am overlooking a very simple problem/solution. If this car wasn't in fresh off the lot condition I would sell it for money to put into my grandfathers 70 camaro that I am also working on.. but I would get very little the way it runs currently.

I just need to get this car running right, at which point I would love to drive it and take it to some shows and meetups. I would love to get this handled myself with some guidance, but I am absolutely fine sending it to a qualified shop/mechanic in Hampton Roads or anywhere in Virginia if need be. The parts i've replaced that haven't fixed the issue would have already covered transporting the car twice!

If there is an SC guru here that can spare some time for me, I would greatly appreciate it.. or if anyone knows a shop with a supercoupe/xr7 genius, help me get in contact with them please!