Bad injector/connection?
 

A couple months ago I had my car down for a while because I was installing a new radiator and a PFS SMIC. Car ran great before the mods, but after the mods I noticed the car began to jerk a little under moderate throttle. I just ignored the problem because I was hoping it was a tuning problem with the car and I was planning to get tuned by Kan later. I drove the car very little and very lightly between the install and the tuning session.

So my car is on the dyno, and Kan says theres something wrong because the car keeps detonating......he says it seemed like one of the secondaries was failing. With the help of some others at the shop we remove my secondaries and replace them with some ones that should be working fine. I noticed the harness for one of the injectors (the wiring harness not the injector itself) is missing a bottom half. Put some silicone around the connector and put it on. Kan took it out on the street and said it seemed fine now.

So now after the tuning, I noticed very light jerking/bucking still! Its wierd because its only at part throttle, normally @ <3000rpms. If you step on it the car takes off no bucks or anything. I can't imagine replacing a bad injector and having the replacement be bad as well, the connection should be fine it shouldn't have gone anywhere......

Any ideas before I tear her apart again? I'm going to check the TPS voltage readings later but they should be in spec unless it got bumped during the UIM remove/install....plus that dosen't really explain the problems prior to the UIM removal.....

Any ideas are appreciated.....

New wiring harness.

If you have one that's got brittle and broken connectors, then every time you go to fiddle with it or repair it, there's likelihood that you'll create a new fault in the wiring.

If your harness is not all brittle and fragile, try to repair that one connector (you should have no trouble finding a replacement injector connector and splicing it in). But if there is any doubt I'd replace the whole harness. Odds are some other wiring fault will appear, and there are few problems as irritating as intermittent wiring problems.

Dave