over the past weekend, my engine decided to start running really rough. it's a '88 with a 2.8 and auto trans. now here is what i know.

1. Oil pressure- when i start the car, the pressure is around 60 psi, and after about 2 miles of driving, it slowly decreases and once it hits around 40, it just drops all the way to 0. but it has always done this and i'm not sure if it's just the sending unit or not.

2. it starts vibrating at idle, then when i press the gas, you can see the tach needle vibrating badly and the car sounds like a lawn mower. eventually, if i get the rpm's up enough, it will smoothen out, but always starts again and jurks a little at highway speeds, where the tach is at 2200 or so.

if i were to guess i might say the oil pump, but i'm no mechanic. also there is a ticking when it's running rough at idle

 

Hmmm...need more info for good advice, but the first thing I would do is replace that sending unit...I think I would like to know if I have oil pressure or not...kinda important...you know? ;-)

How long has it been since you did an all-around tune-up? I know that sounds simple...but plugs, wires, cap, rotor, fuel filter, pcv valve, and 02 Sensor.

Check your ignition timing! Maybe pull it back a little...

When your oil pressure gauge drops to 0, does it start ticking loudly from the engine, like someone is beating on the block? If so...you're losing pressure and it's your lifters that are knocking. I don't know how hard it is on the smaller engines, but you could also pull the oil-pan and replace the pick-up screen, but if it's to that part you might as well de-gunk the whole engine.

Also...as far as running rough goes...Remove the EGR Valve and de-gunk it, it could be stuck open and cause the car to run like crap. Won't solve it all but could help.

Hope this helps man.

 

i've changed everything recently except for the o2 sensor. as for ticking, the only time it ticks is when it's at idle and starts acting up. when it does act up though, i can sit there and watch the tach jump around with a varience of about 300 rom's, and if i drive off, it feels like it has half the power and is really slugish. i haven't ever taken the oil pan off, so i'm not 100% on if there is anything in the way or not, but i have taken them off of other engines before.

oh yeah, the ticking almost sounds like it's directly in the middle of the block...which sounds to me like the cam, but i'm not sure.

i'll try changing the sending unit and o2 sensor asap and pull back the timing and see what happens from there.

thanks for the help so far.

 

Sounds like you are losing oil pressure. If you are your lifters won't expand because they are hydralic. That would cause the ticking or knocking noises. If you have no oil pressure and your lifters are't expanding, then your valve timing will be all off. That would cause it to run like a *bleep!* If your oil galleys are plugged or filled with sludge, the only way to really solve the problem is to have the engine pulled, disassembled, and Hot-Tanked or Vatted to clean out all the passages. You could use motor flush to help a little, but it the condition it seems to be in, it will hurt your engine even more. First find out if you are getting oil pressure or not, if you're not...you have to go from there man.

Good luck! Hope this helps!

 

after driving it a little today, i found that the rough running is continuous even with oil pressure of 40 psi. i found one plug wire not on all the way, so i fixed that real quick and it seems to give it back a little power that seems to be lost.

i located the ticking to not be on the engine. it's on the part that the middle plug wire on the distributor cap connects to on the other end. don't know what it's called...i'm no mechanic.

at highway speeds, if feels like the engine jurks a little every few seconds.

also, if it helps, i know my tranny is probably fixing to go out. the last time i changed the tranny oil, there was a lot of metal shavings and it smelt like crayons.

i plan on switching the engine and tranny in a couple of months, but i need this one to last until then.

thanks for the help.

 

Man...I dunno.

The coil?!? The Rotor? (Inside the cap?)

Tranny is a whole 'nother beast.

 

so you live in tyler...i have a friend that either still lives there or used to live there. he drives a black '97 mustang gt. his name is logan rogers.

i'm going to check all the ignition crap as soon as i can, which will probably be the weekend. are there any secrets on how to check this stuff out to make sure it's working properly?

 

found the problem. i either have worn valve guides or piston rings...i found oil all over the no. 3 plug....even though i've recently replaced all the plugs and wires.

also, the no. 4 plug was bridged, causing the cylinder to be dead.

what could cause this to happen so suddenly? 2 weeks ago, the car ran fine.