sudden loss of get up & go

[j894]

Out of the blue this week, my truck seems significantly down on power.
Cant get up the hills as fast or accelerate as fast (not that it was anyway, hah).

I checked & cleaned My MAF, & IAT sensors. Checked air filter, all good.
Clutch isnt slipping. No codes. Plugs wires, Cap & rotor are maybe 9-10 months old. MAP sensor is only a few months old. Didnt put the wrong gas in it.

Havnt touched anything in weeks. Seems to have happened overnight?

Havnt had to troubleshoot anything like this in a while.
Anyone wanna throw any ideas out?

[droopy89]

Mine did the same thing about a month ago, its better now though, all I did was spray some throttle body cleaner, and when i say some i mean a whole crap load, and that seemed to help, but im about to get all new plugs, distributor cap and rotor and new plug wires so that should help a little more. Mine has 112,000 miles on it if that helps any.

[Hammer Head]

Did the inside of your cat come loose? Just a thought.. had a car that the honey comb came loose on & whenver I'd accelerate it'd move & almost kill the engine. Power sucked big time until I changed it out.

[DetroitMuscle]

I got the same problem, I was told check the timing and EGR, and if the o2 sensor hasnt been replaced, replace it. I was told they are only good for 100k at the absolute most.


Crawl under it and smack the cat, see if its busted up or solid sounding.( a good cat will give off a echo, a broken on a dull thud.

[1993blazerlt]

could it be becasue of carbon build up? Try running a can of seafoam through the engine

[Sparky2263]

How has fuel consumption changed?

[droopy89]

It should decrease by a few mpg, at least mine did, but it back to normal now

[j894]

I have to see if it is getting worse now.
I was beating the **** out of it the other day before I filled up, so I'll have to see if it changes after I get back from work tomorrow

[droopy89]

let us know

[Sparky2263]

Winter fuel is getting delivered now. More volatile, less dense, lower mileage. Mine has dropped about .5 mpg. I rarely get on mine these days so fuel mileage has been excellent with no A/C compressor needed either. Actually got 19.7 one tank. Seems high but it was 80% driving at 60 mph.

[nomaboy]

yea, damn winter...

[j894]

I thought of that but it seemed to happen overnight, I didnt put any gas in it or anything till a few days after I noticed the loss in power. Just seems less ballsy.

Unhooked the battery for 10 minutes to clear everything. Still no help.
Damn I wish I had that tech II to see whats going on.

[Maximus]

Winter fuel is getting delivered now. More volatile, less dense, lower mileage. Mine has dropped about .5 mpg. I rarely get on mine these days so fuel mileage has been excellent with no A/C compressor needed either. Actually got 19.7 one tank. Seems high but it was 80% driving at 60 mph.I was just getting ready to post that.I know that within the last month they have been using Winter fuel around here.I didn't even have to ask I knew from the way the truck was running and my mileage.That is one of the things I hate about winter is the poor gas.I usually run a good home brew fuel additive to help performance with my truck through the winter months.It's a simple one that most old school gear heads use but with a little new school added to.I aint gonna post it because if someone made a mix themeselves and screwed up I dont want them blaming me.Im sure Sparky knows what I am talking about.

[j894]

You talking about mixing @S$it0ne in the fuel....?

Anyway, I didntadd any fuel to the car or anything.
Its like I parked it & came back it was different.

Gonna fill up tomorrow once I put some more miles on & will report, LOL.

[Maximus]

Could be just bad gas or something and no Acetone.Acetone has a high octane rating but that isn't wat I use.Most fuel additives and cleaners all use the same chemicals.Even gas companies add some of the same chemicals to keep injectors clean.They just blend in a certain amount of these chemicals at a certain concentrate.I like a bunch of other people make my own.I have been doing this for years and it's always worked great.I run it in all of my vehicles.I even made a certain mix for my TA everytime I take it to race.Not one sound of ping or data shows any knock or detonation.But some don't know what they are doing or expect to much out of stuff and try to substitute it only for a higher octane gas.Which is not being realistic.But if used right can keep a fuel system clean and running efficiently.But anyways try new gas and but a good fuel stabilizer/cleaner.

[j894]

Mileage is roughly 17.5mpg+, combined city & highway.
Overfilled it a little bit.

Another weird thing.
If Im flying on the interstate in 5th. And nail it, i hit 90 faster if I leave it in 5th & punch the gas, than if i down shifted to 3rd or 4th. I understand peak torque is around 2,800rpms, hit 90 @ about 3,000rpm. But when I looked at the engine dyno graph it has (before 2,800) & maintains most of its torque to 4,400rpms.
Seems like just after 3,200 it dies off. (although, its been like that since I got it)

Am I looking at restricted exhaust or something? Or is the timing or A/f ratio changing after a certain RPM?

Im looking for high speeds with this truck just using that as an example.

[Sparky2263]

Sure as heck is starting to sound like restricted exhaust to me.

[Hammer Head]

mmhmmm. Like I said check the cat.. & muffler. How many miles are on that exhaust of yours? Maybe it's time to step up & replace the main pieces.

[j894]

Assuming it hasn't ever been changed. 109k
Was thinking about getting a custom dual exhaust next year. heh

[Hammer Head]

hehe yea maybe it's about time. you could always do a single 3" exhaust. Take the header pipe from an Astro (the pipe from the manifolds to the cat) it's 2.25" that merges into 3".. has a single O2 sensor bung already there. I don't know if you'd want to do that or not. The convertor from the Astro has a 3" inlet & then goes down to 2.5" & if my memory serves me correctly the rest of the exhaust is roughly the same shape as the S10 pickups.. maybe minor mods needed to fit. Just a thought for better flow & a somewhat cheaper solution because it'd all be stock (maybe just throw a flowmaster at it).

[j894]

I was thinking dual 2" or 2.25" into hollowed cats, Then into stock sounding mufflers. Keep it quiet & non-obvious. Something that shouldn't restrict the flow of one bank too much.

Eh just thinking out loud. Need the $ to do it first. Alignment & 2 tires set me back, still need 2 more & a wheel bearing. Now accepting donations. hehe

[droopy89]

I Now accepting donations. hehe

We all need donations for different things, so... get in line

[Hammer Head]

And I still need a job.. I've got more than enough time to do mods but.. income just isn't there for it. haha

[j894]

Well, I know this thread is old.
But I found my vacuum gauge, Im pulling 22" at idle, roughly 1" at WOT.
Thats with one of the true-flow filters, cut Air box, TB restrictor removed.
Doesn't seem like a major exhaust restriction? Doesnt seem like 1" is a lot, but hell IDK. My '93 pulled 3" at WOT. LOL

Also noticed a Tick on the drivers side of the motor ..... ****!

[j894]

up.
any opinions on the vacuum reading?
is 1" significant?

[Sparky2263]

1" is fine. Meter ain't that accurate that far down anyway.

[j894]

Ah, ok.

Just curious, what kinda reading would assume a significant restriction? 5" ++ ?

[Sparky2263]

I like less than 1" of Mercury.