sciff5

iTrader: (1)

So like I said in my other post yesterday I got stranded on the side of the road and it turned out that the signal wire that comes from the pcm and energizes the relay came loose off the back of the fuel pump switch I'm running. So once I figured out what it was it was a 5 min fix.

Before the car totally died it had started sputtering and bucking (mainly at low rpm like when your cruising in a high gear) randomly. Usually would only buck or sputter a for a couple seconds and then smooth out.

Well after I fixed the fuel pump wiring I figured this would go away as it was probably caused by that wire being loose. Today I drove the car 50 miles and it started bucking. I actually thought the rear end was seizing up and I started getting really nervous. Before I left I opened the fill plug on the rear end to see if it needed fluid and about half a quart of fluid came out on me. I guess it was overfilled. Tightened it back up and the diff hasent been giving me any issues. Doesnt whine or anyting really. It bucked for about a few seconds at a time and during the worst sputtering it let out a big backfire and then again smoothed out.

I used to have an issue with the connector that feeds the coil packs on the drivers side and 2 wires in that connector were loose so I jumped the connecter and soldered in another connector. I've traced those wires all the way through the harness and all the way back to the pcm and they are perfectly fine. So the wiring looks fine but I still feel like its dropping those 2 cylinders intermittenly. I pulled over the car on the highway got my infared thermometer and checked the temp of the primaries and they were all about 330-360 degrees. So no dead cylinders. I shook the wiring (where the loose connector used to be and it didnt drop any cylinders) I pulled the codes and there was none, it wasnt pulling any cylinder misfires...but I've found in the past that the car really needs to be misfiring consistently to even pull a code.

When I got back on the highway I did a quick 1st,2nd, 3rd gear pull and the car was normal and stayed fine for the last 15 or so miles of the trip.
Thinkin about bringing it to Don (slowhawk) but I'm not sure I could even duplicate the issue once I got there because 98% of the time it runs fine.

Only thing I can think of is clogged injectors which I'm not sure would make an engine buck like that but that backfire leads me to believe I'm not lacking fuel.. but having a spark issue. Only reason I think it may be injectors is because I have been doing work on the fuel cell, drilling it out for a fuel level sender (cleaned it out well afterwards, and I have a really nice new fuel filter inline before the pump but who knows)

Any ideas guys? I'm getting a little gun shy about driving this thing over long distances.

5.3LJimmy

iTrader: (10)

Sounds like you may have a loose connection on the crank position sensor. May want to replace the connector as it's pretty cheap to get a new pigtail from the dealer.

sciff5

iTrader: (1)

thats a good idea but if if was a loose connection to the crank position sensor wouldent it pull a code immediatly?

5.3LJimmy

iTrader: (10)

Not necessarily. I've seen this problem with no trouble code present.

lakelife79

A car I was working on recently was bucking and doing strange things recently it ended up being he was low on fuel pressure.

98RedBird

iTrader: (77)

Check the grounds too. That will most definitely cause an intermittent problem. There is one on the back of the drivers side head that grounds both the coil packs as well as the injectors. That can cause the symptoms that you're describing. Just a thought.

If all of your grounds are tight then move on. But wiring issues, grounding issues mainly, as I'm sure you know can cause all sorts of headaches, so eliminate them first. And every time a code does pop up read it. It will more than likely just tell you that it's misfiring but it may tell you exactly where the problem is and point you to a sensor or a circuit.

Also as stated, check fuel pressure at the rail. If it's low replace the filter and work from there. It may be the pump or it may be injectors if you have good pressure at the rails. Have you had the fuel system cleaned lately?

sciff5

iTrader: (1)

I was going to get some techron fuel system cleaner and put it in there for good measure.

I do have a cheap summit gauge that is shrader valve I just need a female/female shrader valve connector to mount it on there.

sciff5

iTrader: (1)

Put some fuel injector cleaner in there just for good measure and drove the car around today till the bs started. Seems to happen more likely when the car is hot/warm after I've been driving half hour to an hour.

Car started sputtering really bad and more gas just made it sputter more and more. the sputtering was enough to get me to the side of the road where the car was idling around 500rpm and still idling really rough. So I jump out of the car get the IR thermometer and check the primaries and what do you know all the primaries on the passengers side were about 200 degrees which was about 100 degrees cooler than the drivers side headers which were around 300-330 which seems to be normal, but pretty much as soon as I could get under the hood the passengers side warmed up and the car started idling well again. within another 20-30 seconds all the primaries were even and the car was running normally again

Still no codes being pulled

sciff5

iTrader: (1)

Maf might be bad

I started the car up today to get some chineese I am guessing its still warm from me driving around earlier today. Anyway the car drove shitty almost immediatly after starting it up. Not even 100 feet down the road it started bucking sputtering ect. I pulled over and at the advice of others I checked the MAF. Checked the wiring on it to see if it was good. Unlike all times before the car kept sputtering and didnt smooth out like it used to. Anyway I completly unplugged the MAf and the thing ran the same then I plugged it back in and no change.. its like the car is running without a maf all together.

So I'm thinking the maf might have been dying and finally totally **** the bed on me. Does this sound like a feasible explanation?

CMurph

Have you found a solution to this problem?

My car seems to be doing the same thing and I'm having trouble finding the cause...

groundczero

iTrader: (2)

I am having a similar issue and mine as a carbed swap into an older vette.

CMurph

Wow...so no solution yet?

Here's a question...when it happens to me my advance jumps to ~40 when on the gas, ~4-6 when off...I'm guessing that's not normal...?

m6speed

iTrader: (11)

my car did that, my o2 would die after exactly 50 miles, replaced it and everything is fine now. it did not throw a code either. i found out by scanning the car with hp tuners and watched the o2 read drop to nothing.

CMurph

Which O2 died on you?

1Loudz28

iTrader: (47)

i was gonna say burnt up 02. wont throw a code since its tuned out.

m6speed

iTrader: (11)

pass side o2

crainholio

iTrader: (2)

Sounds like you are intermittently losing the entire passenger side bank. Check the common 12V feed to that bank (INJ-2 fuse?) and the ground. Wiggle the connector (C101 maybe?) and see if the idle quality changes, etc.

That one 12VDC feed supplies voltage to the injectors and coils for the whole bank, so if it's not properly connected you lose the entire side. The fact that all your header primaries on that bank were low temp seems to point the INJ-2 12VDC feed or ground.

evilstuie

It would be awesome if people actually posted what ended up happening so others can find the posts useful instead of just ending them without a solution or at least information to say they couldn't find the problem.

G Atsma

Agreed!

crainholio

iTrader: (2)

Yup, these cases are usually a plea for somebody to fix their car over the Internet. They give up and take it to a garage.