87 Toy Supra N/A, Running on 4 Cylinders
 

Ok, here's the situation:
- Let a friend borrow my 87 Toyota Supra N/A for a few days and when I got it back it was putting. Having reason to belive I was dealing with a misfire I pulled each plug wire with the engine running. Cylinders 3 and 5 had no affect when the wires were unplugged. Assuming bad wires (wires were dated 94) i went ahead and replaced them with Prestolite Pro-Fit wires. At the same time I inspected my spark plugs and found some dirt and grease on plugs 1 & 2 but the electrode and ground were fine. I reinstalled all the plugs, ran the new wires, put everything back together and the car was still misfiring. Assuming my friend was a cheap ass, I refilled the tank with supreme and pulled the injectors to check them for being plugged or gummed up. Nothing noticable, unfortunately I have no other way of testing them other than visually. I put the plugs back in, in a different order, and took the car out. About 20 miles down the road the car starts kicking and bucking like a bull and all power is lost (feels like a four cylinder!) I haven't had time to check what cylinders are misfining now but I wanted some ideas on what could possibly be wrong. Thanks in advance everybody.

- Wil

P.S. I did a compression check and got about 180psi on all six cylinders (variance of about 5psi between cylinders). The engine was just put in about 200 miles ago (used but compression test was good as was leakdown test).

Injectors come to mind.

I also have this problem, new plugs and wires and still have a misfire. It just got worse and worse after a few days. If its the fuel injectors, is there any way to clean or repair them? And some times it gets slightly better, but still misfires, when i drive the car for a long time and get it hot.

Well since it is an 87 N/A, then I am also thinking it has a distributor with rotor and cap. It may be arcing between the 5 and 3 cylinders in the cap itself. Firing order 153624, so that is another area you may want to check. It seems to me you have eliminated just about everything else.


Good luck and let us know,

Russ

Yes, try a new cap and rotor, and check the fuel pressure. Any codes?
TPS and AFM can cause misfires too.

Im pretty sure it was a fuel problem, cause the car idled and revved up perfectly fine, it was just under load. But I put laquer thinner in my gas, and it runs fine now. But ive only had a little time to drive it, because I dont have insurance anymore lol.