hey i have a 87 that i just got this past weekend and the engine starts and runs and all, but it will not rev past 4k RPM. i can drive it but if i step on the gas for too much when it gets to 4k RPM it just wont go anymore. any ideas wat it could be?

i heard it can be air flow sensors, or something to do wit the ECU and air meters or sensors.

any help would be appriciated. thanks in advance

and sorry if this question has been asked and answered already, im new to this forum.

 

It could also be a clogged fuel filter or bad catalytic converters.

 

Check ALL your fuel system components. Everything electrical/mechanical. Your key points of concern should be the boost sensor (passenger-side strut tower) and it's wiring, the AFM (attached to air box), the water-temp sensor (on the water pump), and the double-throttle assembly (on the throttle-body). After you verify all these are working (using an ohm meter), check the fuel system over thoroughly. Check for flow and pressure.

Cats get clogged (if it's factory-stock, it'll have 2 small cats and a large main cat). the first small cat usually gets disentigrated, and it plugs the second, which gets hot and does the same, and then it'll clog the main cat. Generally, if you pull the exhaust system apart and you can see a white substrate in the first cat, then it SHOULD be okay, but don't rule it out (others may be clogged).

After you've checked all the components, and probably re-grounded the engine and the boost sensor, then you've got a fried ECU. When I had a fried ECU, it wouldn't let me press the gas more than 1/2 way without it cutting the fuel to the engine.

There are other things that can cause this (bad gas, not enough voltage to fuel pump, bad coils/ignitors, bad timing, bad injectors or resistor pack, bad wiring harness, bad Throttle sensor, plugged injectors, ect.....). Just go through it one thing at a time and eventually you'll find it. Don't stress out. More than likely, it's something simple, so keep it that way; nice and simple.

Hope this helps,
Matt

 

thanx so much, i will try every thing u guys suggested and see what happends. ill keep u updated.