weird misfire

[shippy8907]

alright I am hoping someone can give me an idea on where to go from here. I have a miss that is on the number 5 cylinder. The coil is giving off good spark, it even has a new spark plug I just put in it. I even swapped coils to make certain it was not a coil issue, and I have swapped out the injector and I know that it is firing because with the screwdriver technique you can hear it clicking. the miss is only noticable below 3000rpms. anything above that it is either gone or its almost non existent. Also I have noticed that there is only a miss on acceleration. on decel it is very smooth. If anyone could give me an idea on what else to check or if I have missed anything that would be great.

[Z32man]

The problem is your ptu ( power transistor unit) located on your timing belt cover on the passenger side.

[marty1mc]

I actually had the same issue. It turned out to be the PTU harness.

[shippy8907]

i just replaced the ptu so im pretty sure it is not that. So if it were the harness causing the problem could i run wires from the beginning of the harness to the coil and that would point out if it were a problem with the harness? I had also read where someone had the same problem with the miss being below 3k and it turned out to be the injector had really high resistance.

[robomatic12]

Have you checked and cleaned all connectors/terminals of corrosion and debris? Especially the coilpack/injector and ptu connectors.

Also check for any ECU codes

[shippy8907]

yes all connectors are clean and in very good shape. I am leaning towards it being an injector. it has progressively gotten better the past few days. the injector that is in it now is a used one that had previously been in the car. I can hear it firing but i dont think its supplying enough fuel at lower rpm. would I be able to get a code from the ecu even though the check engine has never came on?

[robomatic12]

Yeah some codes don't throw the check engine light (if it works). Use a multimeter to check the ohm of the suspect injector vs. all the other ones. Post here with results

[Z32man]

check this site and it will tell you how to read codes and it says all the codes.
http://www.ttzd.com/tech/diagnostictech.html