Just finished doing plugs and wires on 93 t/a took it for a drive and it's still doing what it was doing before. I thought it'd be the plugs and wires cause they were old. It gets up to about 3k rpms and will not go any higher and just pops. Is this fuel pump or what? It also had a stumble before I did plugs and wires but that stumble is gone.

 

I would put a fuel pressure gauge on the fitting at the back of the intake on the fuel rail and see what it shows.

My car had a bad stumble like that when I first got it and it ended up being the coil.

 

I would check the fuel pump first. That's what I have run into a lot with these cars having that sort of problem. Won't hold pressure at wot. Not a hard job if you make a trap door.

 

get a FP gauge with a hose on it so you can tape the gauge to windshield. watch FP while SUSTAINED WOT....does FP drop?

if it does your pump or wiring is bad

 

Opti....... never count it out!

 

What is considered the coil? Because I just had the opti spark replaced, could it be mass air flow sensor? Someone else possibly injector or need valve adjustment.

 

The red thing here. It connects to your opti spark and is what actually creates the spark for the opti. If you've already done opti, plugs, wires it would be the next spark item most likely. I would test your fuel pressure as mentioned because it doesn't cost anything.

 

OP

it could be several things causing your problem.

You need to start with basics like checking your fuel pressure, especially under the driving conditions the car lays over...3k rpm

if you have good FP than move on to ignition system.

your valves should not need "adjusting" if they are still un-molested stock. Your valve springs could be weak but puking at just 3k rpm they should be able to go above 3k rpm even if horribly worn out. If at some point valves were "adjusted" and the problem started after that than yes you would need to re-visit that procedure. A F'ed up valve adjustment will make the motor run horrible but at all rpms

you mentioned you had a Opti "installed"...and then say "you did" plugs & wires...then asked where the coil is.....if you did "wires"....you had to plug one of them into the coil

If someone else did this work you might want to discuss your problem with that person.

If you are working on the car than shoebox site is a wealth of 411. At minimum get a Haynes service book if not a Factory Service Manual (FSM)

 

Ever replaced the fuel filter?

 

I had the same problem it was the opti.

 

Could be a clogged cat

 

Your '93 doesn't have a MAF sensor.

What was the reason for Opti replacement? What brand did you get?

 

I would check coil and ICM. The ICM is right behind the coil. I replaced both when my 93 would crank but not fire. My opti was also only a few months old. I had the same problem you're having. But if opti is replaced, and also plugs and wires, and you have good fuel pressure. Most likely still a spark issue. But the coil is cheap, ICM is around $100. Easy to replace. I'd check that, personally.