I Have a 94 camaro that hesitates on acceleration, when engine is warmed up. It hesitates until 3000 rpms then picks up power. Lately the car has been back firing through intake when i give it a quick rev. Things i've tried to eliminate problem : Changed( Optispark twice) Plus cap and rotor, New Plugs and wires(MSD), New fuel filter, Removed Cat Converter, Replaced Clutch, New Engine coil, K&N Air Filter. Ive had the car for about a year now and have been replacing parts left and right. I still have not been able to drive the car without hesitation since i bought it. I also replaced water pump, thermostat, Battery,and (Starter.twice). If Any one has had this problem and knows how to get rid of it i would REALLY appreciate the help. Thank you

 

well i would say it would be the distributor but since you changedit i dont know, you said you removed the cat converter, have you tried installing a new/clean one ?

 

I had that same problem, hestitation, stumbling, loss of power,and occasional backfiring. I changed my fuel filter, and then it worked, just fine. However,you did that so I dont know.Have you checked your injectors? Maybe they are bad. I dunno.

 

Your car acting bad only when warmed up idicates that something is happening when it goes into the closed loop mode. If the Check engine lite is lit that problem must be addressed first.
There ar certain sensors that the PCM only looks at when in closed loop mode. You should test or replace the same sensors. These include:
ECT-- Engine Coolant Temp
IAT -- Intake Air Temp
MAP-- Manifold Absolute Press
O2 -- Oxygen sensors
MAF-- Mas Air Flow
KS-- Knock Sensor

Also check
EGR valve operation (should close at WOT)
Idle Air Control valve
TPS-- Throttle pos sensor.

Check the sensors using a scan tool (not a code reader). Verify that all readings from the sensors are within limits and reflect actual conditions. That is, if you know that the coolant temp is 160 deg and the ECT says it is 200 deg, then the ETC is in error.

 

i had the same problem, change fuel filter, spark plugs and wires, and problem fix. had a little problem with the routing and it missfire alot, but i got the routing checked and good, now it runs great. urs who knows they are very complicated.

 

The Next thing iam going to try is the EGR Valuve. I removed the Cat because it was clogged and i thought it would increase HP but a friend told me if i removed the Cat because it was clogged i should have replaced the EGR valve because they work together. Also when i test for codes i get a low coolent temp because i replaced the Thermostat with onethat opens at a lower temp. I was uncomfortable with the engine running at such a high temp especially with aluminum heads. Was it a bad move by using a low temp thermostat? Thanks For The Help

 

Engine is designed to run hot, just keep it below 240.

 

Well the EGR Valvewas not the problem. Next up iam going to try the MAF Sensor. I Dont want to waste money buying the MAF sensor so iam going to try and find someone who has a 94 thur 97 camaro so i can use their sensor to see if thats the problem on my car. If anyone is around Southern California Inglewood area i would really Appreiciate if you could let me try your MAF Sensor. Thank you

 

The car will run without the MAF sensor. If the MAF is bad it will run beter without it. Just pull the connector to disable it.