Intermittent surge?

[jsbihn]

Hey all,
I have this intermittent surge or miss or something.
Basically what it is doing is every now and then, depending on the gear or the rpms, the truck will feel like it is being held back then it feels fine... or it will show on the tach the rpms going up and down a couple of times (usually its goes up or down ~200-300 rpm). It doesnt always do it, and it doesnt always show issues on the tach... ie. the being held back feeling is usually when I am driving or maybe accelerating.

Not sure what is going on. If it is trans related, fuel related, maf related, ignition related, or whatever
Given I dont have any CELs and even when I use my ELM code scanner nothing is picked up... which I know doesnt mean much, but still no CELs.

So just wondering what you guys think it is.... so I dont have to completely rip apart the rig trying to find it.

Thanks

[fyr145]

One of the first things that come to mind is the throttle body unit. It may getting some kind of short thus robbing your motor of power it would normally get.

Another possibility is the accelerator pedal unit. Its that sensor that detects how far your foot is on the pedal. If this is sending the wrong signal to the ECM, you could also be losing power that way. These happened to me a long time ago and I had to have them replaced.

How about the MAF? Is it clean inside? Maybe a spray of MAF cleaner followed up with a throttle body cleaner on the other end might help with these possible issues.

Just my .02............

[HUMTECH]

At what speed does it seem to occur? Could also be tcc lockup coming on and off

[jsbihn]

Thanks for the responses.

Here is the answers to the questions....

I have fogged the engine with seafoam about 6 months ago.... maybe a bit longer and cleaned the throttle body, but didnt clean the MAF.
Though, it has been doing this even before that.
The steady sluggish and then normal thing and off doesnt have a speed. sometimes I feel it sometimes I dont. It is really faint actually when I do feel it, but since I am behind the wheel and my "personal sensors" can detect more I feel it.
Given if I press on the gas and it revs up, usually I dont feel it (like if I am pass someone on the interstate)

One person on another forum did happen to mention that it could be my Cats clogging up.... which I do have to say that I have the BAD rocks in a can noise that are coming from the cats I believe .


Thanks for any help you can give

[Rico001]

Originally Posted by jsbihn

Thanks for the responses.

Here is the answers to the questions....


One person on another forum did happen to mention that it could be my Cats clogging up.... which I do have to say that I have the BAD rocks in a can noise that are coming from the cats I believe .


Thanks for any help you can give

If you have over 100,000 miles I would say it maybe the cat convertors since they are rated to withstand 80,000 by the EPA
Sounds like you need a garage with a lift that does muffler work too to check out the exhaust system

[jmudler]

Cats were my issue with said symptoms. My rig also doesn't like the cheap gas (10% ethanol)