A little vehicle info first.
95 5spd with 150k
knock sensor changed less than 6 months ago
Short ram intake with jwt pop charger


I'm having a problem under heavy acceleration. Under normal driving (shifting in between 2k-3k with light acceleration) the car drives fine with no hesitation. If I get into heavy acceleration the car seems to hesitate just after 2k rpm for about a second and then picks right back up. It also seems if I down shift say from 3-2 it will also have a quick hesitation and then take off normally. I did some searching and found some old threads with many different answers. I plan to go over a few of those tommorrow but I wanted to get some more input first. The main two things i've come up with from searching have been a coil pack or the knock sensor. I did have a code for the IAT sensor which I visually inspected and seems to be ok. I looked at the knock sensor the other day when this problem happened and the knock sensor seems to be cracked down the middle. I have no code for a knock sensor though which is confusing.

All the search results I got came up with a couple year old threads and no outcomes. Just looking for anyone that may have had this problem recently and what their outcome was, or anyone that may know more about this problem. Thanks in advance for any tips or suggestions.

 

2,500=maf

 

I thought if the maf was bad it wouldnt go past 2500. Or is this just the beginning of the maf going bad? I just cleaned the maf about a week or so ago so I can't imagine that just cleaning it again would help.

 

I think that may be coilpacks slowly going out, I think I have read that here before.

 

Yea I believe many people attributed it to the coil packs. I might have the same prob but im not sure yet

 

it was the coil packs, what solved my problem . had no check engine or anything still they were bad or at least one .

 

So how do I narrow it down to just the coil pack(s) that is causing this problem? I know if it was throwing a code i could just switch the bad one to a different cylinder and see if the code follows but since I have no code what's the best way to find out? I guess the first step should be to just take them out and visually check for damage...

 

i didn't bother even checking . most likely you wont see any damage , you would have to test them but that still doesn't guarantee that they wont be failing under heavy load . i just bought a used set from here

 

Well coil packs seem to be a unanimous decision. I just did some quick looking on eBay and found a set of 6 from a 98 i30 for like 70 bucks. I just want to double check that they'll work in my 95. Thanks for the help so far everyone.

 

Yes they will work

 

could be a lazy o2 sensor or maf sensor.They don't always throw a code when they are goin' bad

 

Ok so I got the coils and switched them out and still having the same problem. The problem seems to be most pronouced as I get back into the gas after shifting. It does happen in the 2k-3k rpm range also when giving it say around 50% or more throttle. I'm gonna try cleaning the maf sensor again just because. I think I'm also going to go to radio shack and pick up a resistor to bypass the knock sensor (instead of buying one off of ebay and that not being the problem) just to see if that fixes it. Any other ideas I should be looking into?

 

Check your grounds (the sensor grounds on the lower IM, 2 screws/bolts)

 

i would replace the KS too. It may jus be a minor knock and w/o KS the ECU isnt adjusting. Ebay has em 25 bucks. If you can get to the KS via the org method then u shd replace it. Try to reset the ECU.

 

I just cleaned the maf and cleaned up both the grounds on the lower IM and still nothing. Gonna go pick up a resistor from radioshack and try the knock sensor before I just go order one again (just replaced it >6 months ago). Also I think I'm gonna try switching out the maf from my mothers 99 just to see. Is the 99 maf the same as the 95? I'm guessing it is just making sure.

 

Swap MAFs No problem. U check CPS, CKPS, and plugs. I think u may have a mechanical problem.

Did the problem occur before u replaced KS 6 months ago? U try some chevron techron??? works magic man. see sig

 

I didn't check the other sensors yet. The problem occurred just before changing my air filter to a jwt pop charger. Had a k&n cone on there and it started happening just before I changed the filter which was about 2-3 weeks ago. I did pick up a bottle of chevron techron yesterday but didn't put it in yet cause I still have a 1/4 of a tank and want it to be closer to empty. I was hoping this was a quick fix cause I'm going to Maryland from PA in 2 days but it may have to wait til I get back.

 

This might be way off base, but have you tested the TPS? Maybe you've got a bump in the resistance curve.

 

Did some running around today and stopped for gas before coming home so I put the techron in and filled up with 93. Now I always ran sunoco 91 and never had a problem before. After a short drive after the fill up the problem seems to have toned down a bit. Not completely gone but definatly not as often. I don't know if it's just in my head or what. I did check the TPS just for the hell of it and my multimeter read 4.5 when checking the resistance at WOT. Does it sound like the TPS could still be off a bit?

 

Watch the voltage on the TPS as you open the throttle. IIRC, it should start around .5 and go up smoothly.

 

Sometimes cleaning the maf will not be good enough if its failing. You said it started happening after you put a new cone filter on. Im thinkin maybe the oils from the filter might have damaged your maf, they have been known to do that. I honestly went through alot of troubleshooting on my car to no avail. so I lived with the problems, until my maf took a dump and I replaced it with a ebay bought maf and all of my hesitation and stalling problems are gone.

 

I had that thought in the back of my head too but for some reason I just didn't do anything with it. After everything I check I'm leaning more an more towards the maf. Does the FSM list a way to check the maf without replacing it with a working one?