i just bought an 86 iroc with TPI and other than the hard starts and stumble at 45 i love it, it has alot of power until i hit 45 then it starts to stumble, if i floor it it goes away up till about 65 and then does it again while im still at WOT, it just misses and runs like complete crap with no power when it stumbles. the car doesnt go past 80 either, it just fights to even stay at that speed and the whole time its missing and sometimes backfires through the exhaust, i have a 145 speedo. this has been happening for awhile so i changed the plugs, got a new MAF and IAC and nothing at all has changed, the SES light was on for about 2 weeks and went off like 2 weeks ago and when it was on i hooked a computer up to it and it said "mass air flow burnoff failure" so thats when i replaced the sensor but nothing changed, like i said though the SES light went off 2 weeks ago but i did the paperclip trick anyways and it said i have a code 33 but i cant figure out what else to do, my fuel pump is new, fuel pressure is fine, im stumped, but no matter what it starts hard, it turns over for like 8 seconds then fights hard for an idle for like 4 seconds, it always starts though, theres no vaccum leaks either, the only "mods" are that the smog pump (i think thats what it is, its the pump under the alternator on the passenger side) was removed, not by me though, my timing is at 8 BTDC
ive searched the whole sight and i cant find anyone with even a similar problem either

 

Have you checked/replaced your plug wires?

 

Check your relays on the firewall on the drivers side by the brake booster. Pull the connectors out gently and clean them really well, and put dielectric grease on them.

The connectors can get really dirty or corroded and sometimes the wires actually pull out the bottom.

Also, what condition is your MAF connector that actually plugs into the MAF?
Pull that connector out and clean it and grease it as well. If the tab is broken that secures it in place, I would seriously consider replacing that connector.

The three relays on the firewall are MAF power, MAF burnoff and Fuel Pump.

After checking to see you have correct voltage going to the relay, and your connectors are in good shape, I would replace the relays.

The other thing I would check is the TPS sensor to make sure its at the correct voltage setting at idle.

Code 33:
MAF sensor indicated an air flow of 45 gm/sec or more for 1 second when TPS was less than 1/4 throttle and engine speed was under 2000 RPM.

The maf burnoff problem is actually code 36.

Trouble codes:
https://www.thirdgen.org/service-eng...ht-error-codes

 

When my TA was hesitating and backfiring, I had the fuel injectors swapped out. Runs like new again. If you have not found another problem, think about the age of your injectors. Mine lasted 150K but I was probably suffering the last 20K and not knowing it!

 

figure it out yet? You said you just bought the car I would do the cheap standards up front and work my way up. I do this regardless what the seller says... New air filter? Fuel filter? plugs/wires/cap/rotor? And other things that would not effect the motor puking out(the prior will). The other Ideas listed above are great possibilities as well. Good luck!