Ive got three codes 0303 0302 - which are both front o2 sensors and and EGR code 0503. The car hesitates / stalls and loses power from idle until about 4k or until I mash the gas pedel. This problem comes and goes. Sometimes it does it other times it runs just fine but over the past week it has gotten worse and worse.

I recently (within the last 5k miles) replaced both o2 sensors and I think my EGR needs to be cleaned to take care of that code. I did clear the codes and none of them have come back after 250 miles but the hesitation problem is still giving me problems.

I was thinking MAF or coilpacks. Any other ideas/suggestions?

 

Sounds like the coil's test them out first and then take it from there

 

I think your right. I swapped it out with a spare MAF and it still has the same problem.

 

Check the tps.

 

If it hesitates and your O2 sensor is throwing a code, your A/F mixture is off which points to the injectors or coils in that bank.

 

Nice. Thanks for this. Ive got to check both banks then because it has codes for both o2 sensors correct? Im going to oHm test the packs this evening.

 

Okay. I cleared the codes and the front o2 sensor and 0503 egr code came back. All three front coilpacks tested at 1.6 or 1.5 ohms (I tested them when the car was hot). When I pulled the plug while the car was running it did effect the idle but didnt cut off. Any other ideas?

Ive got to get this running as I dont have my harness finished yet for the 3.5 swap.... arg

 

I think you got this right. I checked the TPS last night after checking all the coils (all the coils checked out correct). The TPS has 500ohms at idle but goes up to only 1000ohms at WOT.

 

Interested to see what u find here....ive got same hesitation issue without those codes. Ive replaced/swapped coils, plugs, ks n its harness , maf. Cleaned cam and crank pos n ref sensors. Tested both front o2 sensors and cleaned egr tube, iacv, tb n maf.....nothing has helped...im thinkin my crappy egay intake has a small leak, hence my wtb cai thread lol. Im gonna test my tps tonight n c what i come up with n if it matches urs.

 

Oh also ohm tested all injectors and theyre within spec. range.....sry cant edit im on my phone.

 

I haven't checked the injectors yet but all three front coil packs tested right at 1.6. The rear coilpacks (which are 5th gen because I've got 00vi) all tested at 1.8.

 

Alright Im at a loss here. Turns out my fuel injectors, coil packs and tps are all good. I tried going through each one and unplugging it. The "missing/hesitation" that I have is not that of a misfire. Its a total different sound/feel....not nearly as dramatic or apparent as when i directly unplugged an injector or a coilpack. My TPS was fine....it was my cheap multimeter that was faulty.

I did notice one thing though....I had to bleed my brakes today and as I had someone stepping on the brake pedal the idle and "hesitation" I have been having a problem with got worse as they were stepping on the brake pedal. My only conclusion to this is a vacuum leak because the only thing I can think of why this would effect the idle is the vacuum to the brake booster.

Any ideas?

 

Do you get any light dimming when you press the brakes? If you do it would point to a ground problem, other than that I would say check the plugs and the gap on them.

 

Check voltage output of alternator at idle