Bought an 88 RS with a 2.8, 5 speed. ($1200) Ruled out head gasket issues, as suggested by previous owner by simply replacing the thermostat. Still getting rough idle.. Checked the plug wires. Found one that the boot was split on, and a couple others that were melted. Bought a new set from Advance Auto, $16.99 (after 20% off) replaced all of the plugs, and repaired a vaccuum leak on the metal slinky looking hose that comes off what I think is the EGR. Idle has smoothed out, but I have very low, (embarrasing) power.. If it were an automatic, I bet it would barely take off from a red light. The odomater is a five digit at 50,900...Im guessing 150,900 actual. I know sh%t from shine-ola about messing with a 2.8. Any help on what to look for next? Clogged cat? IDK... I have antique/classic car plates, I can can completely remove the cat-converter, legaly. Does not require inspection or emmisions test.

 

fuel filter, possible cat, all the vacuum lines, cap/rotor, air filter. the stock 305's are pretty slow, I wouldn't expect too much out of the 2.8l

 

No need to be embarrassed as long as it has antique plates. People expect cars with those plates to move like a Model-T.


Does the engine still have any rough or erratic running issues when driven under load?

If not - if the engine seems to run basically correctly, no crazy stumbling problems or apparent misfiring, but just lacks power, then the explanations I can think of would be ignition timing, dead or weak cylinders (either caused by low compression or dead injectors), maybe slipped valve timing, an exhaust restriction, or somehow not getting air into the intake (for whatever reason).

Check ignition timing. Make sure you disconnect the ESC wire. Somebody might have forgotten this step. If you leave it connected when you set the timing, you'll end up severely retarded.

You could try removing the O2 sensor and see if it improves. That opens up a little bypass. If you notice improvement then there's probably an exhaust restriction.

Make sure the throttle actually opens as it should and there isn't something seriously wrong with the linkage.

Since you're new to the engine - are you sure it's not running on 3 cylinders? These engines use batch fire fuel injection. The injectors are divided into 2 banks of 3. The 3 injectors in a bank are wired in parallel - if one of the injectors shorts out, or if you blow a fuse or have some other problem in that circuit, you will lose all 3 injectors. The 2.8L will run on 3 cylinders.

Check your fuses - you might have a blown fuse for one of the injector banks.
If the fuses are good, I'd stop there and check compression next.

Even if you solved the problem with a fuse, check compression anyway. You just bought the car and it's good to know where you stand with compression.


If compression is good and there wasn't a blown injector fuse, try to check the resistance across the terminals of each injector and see if any are shorted. They should all be higher than 12ohms.


I'd be tempted to check fuel pressure as it runs just because it's a general thing I always like to check when dealing with an unknown. However, if it's not running erratically then I don't think this can be the problem (if you were getting insufficient fuel for the amount of incoming air then it would misfire).

 

" Check ignition timing. Make sure you disconnect the ESC wire. Somebody might have forgotten this step. If you leave it connected when you set the timing, you'll end up severely retarded." "Check your fuses - you might have a blown fuse for one of the injector banks.
If the fuses are good, I'd stop there and check compression next." These two things I can do today after work. Thank you, that was a lot of good info.