5.0L (1979-1995) MustangTechnical discussions on 5.0 Liter Mustangs within. This does not include the 5.0 from the 2011 Mustang GT. That information is in the 2005-1011 section.
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Need Help! Lots of Questions, just got a 1989 Cobra 5L
Hey just joined this forum hoping to get lots of good advice and info on my 1989 Stang. Allways wanted one found a pretty nice black one. Full body kit ect. Guy said engine was rebuilt to a 307. Looks like its in good shape, minor oil leaks. SOunds clean, runs smooth in neutral when i rev it up to 5 grand or so no knock or pings or shaking. Has plenty of torque. Just starting to run into lots of problems though. Noticing when im driving down the highway, hit 100 kmPH, the car violently starts shaking, only at that speed though. it sucks, i dunno what to look for or check other than driveline, like tranny, driveshaft, clutch? who knows.
Also I have my engine light coming on once and awhile, it just comes on and goes once and awhile, mostly at night time when i have my lights and everything on. Its weird. And tonight I was driving it hard for the first time and its very fast and powerful, goes sideways easy. Except every once and awhile, ill punch it and it pulls like hell up to 3000 rpm then its as if the power just dissapears, like the tires will spin up to 3000 rpm then they stop spinning in 1st gear, even on wet pavement its really weird, its as if there is a governor cutting the power in half after 3000 rpm, and sometimes it doesn't do that though, sometimes it will go through the entire rpm range with no problems, but only when im easy on the throttle, ? it has me stumped any help would be great. Also when im running her kinda hard, ill stop at a stop light and push in the clutch and my car will be reving at 2000 rpm and doesnt go away unless i turn car off and restart it. Heard about getting a computer thing to hook up and see what codes i get, but i have no idea what to get and how much id have to spend.
Bought this car to work on thru winter, so i have a nice running fast car for spring and summer. So i have lots of time. And the guy put after market Halo lights in it looks real good, but they are screwing up my voltage when i turn them on, and he said theres been a new alernator in it. I heard of people having to get new computers for these cars could that solve any of my problems?
Anyways any help would be great! i luv my car just want her to run right, and apprently it has 289 gears in it.
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Firstly there were no 1989 Cobras, Cobras came back out in 1993.
As far as your issue goes it could be a lot of things but two biggies would be a failed sensor (your check engine light may be revealing that) and or a blown gasket (due to sudden power loss, but could also be caused by the sensor.
5.0s are funny little cars because not all the times do the engine code scans work because the ECUs are so old, in short the scan may show everything works fine when really there is an issue. Ex. my 5.0 had this problem with the EGR and throttle position sensors, both were failed but the scans did not show them as failed because they were still on, just not sending proper information. I mainly had problems once the car became hot and when turning it on/off/on again.
Sensors to look at would be the EGR, salt pepper shakers, throttle position sensor, intake air temperature sensor, air intake control sensor, and MAF. All can go out and still not fully trip a code on a 5.0 and cause similar issues as to what you're having.
Also keep in mind it may be more than one of these sensors and usually it is. In short if you have the money to do so, I would change every one of these sensors, odds are they never been changed on the car and if not it's about time they get changed, remember these sensors are over 20 years old. I would also change the EGR valve while you're at it if it's still on the car and not removed by a previous owner.
Sweet thanks for the reply, And about it not being a cobra, i checked the VIN and it says its a cobra, built in Usa, has the badges on it as well.
Unless someone put them there, but either way its no big deal i got my favorite car out there.
But ya, i guess i could change all those sensors, the previous owner said something about a throttle position sensor, but i heard that one needs proffesionaly done. That's what I was thinking tho changing all the sensors that i can. And there's quite abit done to the engine, and it looks like there are vacuumm lines that are not connected to anything, but yet there is nothing around them that i can see that they can be hooked up to. I guess i could take some pics of the engine and see what you guys think. Also there is this guage on my engine, under the hood i dunno what it is. I think it may be fuel pressure?? it reads 40 psi i think.? i dont think its oil pressure because there are aftermarket guages inside for that, but the oil guage is not working at all. Im guessing its the sending unit. Iknow the guy said theres some high pressure fuel thing that was put in, like something about 20 pound injectors i think..He said its ready to be supercharged. Um...Im hopin its nota gasket, but mabee it is. I dont think it is cuz it seems to rip sometimes, and sometimes it doesnt. I guess i just a need a huge tuneup, but anything i could do myself would be awesome so i can save money.
Iknow the car has alot of km's on it, but they seem to all do. And this cars gears were changed so i hear that messes the KM guage, like it says there could be 120 000, but hey it might have 190 thousand right..but yeaa, i definately wanna fix this car up so i can race it this summer!
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