running rough

[7echo]

Started the truck this evening and it was running rough. Idle is a little low. Every now and again the RPMs pick up a little and it smooths out for a second. It runs rough at idle and all the way up to 60. If I get on the accelerator pretty hard the check engine light will flash, then go off. I tried to check for codes multiple times with scan gauge and no codes show up.

Any ideas on where to start?

 

[WEIMY12]

A/F sensor? Oxy Sensor, Plugs, wires, all good places to start... how many miles? I had similar issues, but no CEL light, but was throwing codes, first replaced my A/F Sensor then all plugs and wires (plugs were burnt, and wire to Cyl 6 was burnt through)

 

[TXLX1]

Could be a vacuum issue or cam / crank position sensor as well. If the light flashes there might be a pending code in the obd2

 

[johnbyebye]

A flashing CEL is indicative of an active misfire condition.

 

[7echo]

Currently 120,395 miles. Installed new NGKs at 100,000 miles, Oct '14. Purchased the truck in July '14 with about 99,000 miles.

I replaced one O2 sensor a year or so ago, don't remember which one. It came with plug wires that say '5mm silicone Made in USA' so not original, but not necessarily good ones. Cleaned the MAF soon after I got the truck. Did tranny drain and fill several times.

It has been fine til this evening.

 

[7echo]

Sorta seems like a coil pack issue, but why no code?

 

[mtbtim]

Have you cleaned your throttle body yet? Also, the IAC (Intake Air Control) Valve could be gummed up.

I'd remove the throttle body off the upper plenum and then remove the IAC off the throttle body. Clean them both up really good with throttle body cleaner and then reassemble.

If you've already cleaned the throttle body, many have reported an idling problem afterward because they let the cleaner run-off to drain into the IAC and then the IAC gets gummed up.

Here's a video I saw on the subject that seems decent. Good Luck.

https://youtu.be/2-V1P9dReis

 

[baja1]

uh oh....same symptoms mine showed.....on the way to head gasket failure...

 

[7echo]

I got a code this morning. 0300 and 0306.

I swapped the coil packs between #3 cylinder and #1 cylinder. Ran rough and set code 0306. I cleared that and it re-set, 0306.

Seems this rules out coil pack?

I am cleaning the throttle body and IAC.

I read it may be an injector.

Thanks for the comments so far. Please let me know what you think considering the 0306 code. The T4R is my daily. My back up is out of commission as I am in the middle of working on replacing the upper and lower control arm bushings('93 Silverado), so I am going to have a Christmas repair extravaganza...

 

[johnbyebye]

I got a code this morning. 0300 and 0306.

I swapped the coil packs between #3 cylinder and #1 cylinder. Ran rough and set code 0306. I cleared that and it re-set, 0306.

Seems this rules out coil pack?

I am cleaning the throttle body and IAC.

I read it may be an injector.

Thanks for the comments so far. Please let me know what you think considering the 0306 code. The T4R is my daily. My back up is out of commission as I am in the middle of working on replacing the upper and lower control arm bushings('93 Silverado), so I am going to have a Christmas repair extravaganza...

0300 is random multiple misfire and 0306 is misfire on cylinder 6. This goes hand in hand with the flashing CEL you described in the initial post. Fuel or spark is your best bet for the source of the problem. I've been down the 0300 road before and it was my spark plugs.

 

[7echo]

Cleaned the IAC and throttle body. Still ill.

Another symptom I noticed today-
It is using a lot of fuel.

Still setting code 0306.

I can get a fuel injector for about $130 at a parts store. I usually use Rock Auto or Toyota Dallas but I need it working sooner than waiting on parts delivery next week.

 

[Roland]

I got a code this morning. 0300 and 0306.

I swapped the coil packs between #3 cylinder and #1 cylinder. Ran rough and set code 0306. I cleared that and it re-set, 0306.

Seems this rules out coil pack?

I am cleaning the throttle body and IAC.

I read it may be an injector.

Thanks for the comments so far. Please let me know what you think considering the 0306 code. The T4R is my daily. My back up is out of commission as I am in the middle of working on replacing the upper and lower control arm bushings('93 Silverado), so I am going to have a Christmas repair extravaganza...

Been there, it is most likely an injector. Had pretty much the same symptoms. My guess is in the next few times you drive it your check engine light will come on and stay on.

 

[johnbyebye]

Cleaned the IAC and throttle body. Still ill.

Another symptom I noticed today-
It is using a lot of fuel.

Still setting code 0306.

I can get a fuel injector for about $130 at a parts store. I usually use Rock Auto or Toyota Dallas but I need it working sooner than waiting on parts delivery next week.

I would start with the injector at cylinder 6.

 

[7echo]

The cleaner insulator tip is from the #2 cylinder. The dirty insulator tip is from the problem cylinder, #6.

There is one injector in town, store is open today.

I am going to swap the 2 plugs, just see if any thing changes.

Then I am going to swap the #3 coil pack with either #5 or #1 for one more test of that set up.

Any comments on the plug differences?

I reckon I am still looking for an easy(or easier) fix before taking the plenum off, lol.

 

[BamaDrewski]

The cleaner insulator tip is from the #2 cylinder. The dirty insulator tip is from the problem cylinder, #6.

There is one injector in town, store is open today.

I am going to swap the 2 plugs, just see if any thing changes.

Then I am going to swap the #3 coil pack with either #5 or #1 for one more test of that set up.

Any comments on the plug differences?

I reckon I am still looking for an easy(or easier) fix before taking the plenum off, lol.

Just a recommendation....it may be your TPS that is contributing to the problem as well. If you replace it, get the OE version and not the aftermarket. (Trust me...know this from experience!)

 

[mtbtim]

The cleaner insulator tip is from the #2 cylinder. The dirty insulator tip is from the problem cylinder, #6.

There is one injector in town, store is open today.

I am going to swap the 2 plugs, just see if any thing changes.

Then I am going to swap the #3 coil pack with either #5 or #1 for one more test of that set up.

Any comments on the plug differences?

I reckon I am still looking for an easy(or easier) fix before taking the plenum off, lol.

Switching the plugs sounds like a good idea because that dirtier plug could be fouling. Question is, what caused that plug to foul?

Here's a couple good articles related to your problem:
Spark Plug Fouling
DIAGNOSING MISFIRES

 

[7echo]

Installed new injector in #6 cylinder. Got a little better but still rough idle and sorta stumbling, running rough under acceleration. It did not set a code on the test drive but it still isn't right.

[MENTION=25434]BamaDrewski[/MENTION] suggested a TPS, I will take a look at that in the morning. Can't get one but I will see if it can be cleaned.

The oil looks clean, the tranny fluid looks good.

I cleaned the throttle body and IAC, swapped coil packs around, swapped the 2 and 6 spark plugs.

Let me know what to check next guys.

Here is a pic of the old and new injectors.

 

[johnbyebye]

You may want to verify that you are getting a good spark at cylinder 6, since that's the one that threw a specific code. If you aren't, then the other cylinder that that coil is attached to may not be getting a good spark either. Remove the fuel pump relay and remove the spark plug at cylinder 6. Set it somewhere with the wire attached and crank the engine. If you have someone to watch the spark/crank the engine it will be easier. Verify if there's a decent spark on that plug. I'm not entirely convinced that you don't have a spark issue...

Cheers.