Engine losing power?

check your fuel pressure, if it's TBI it should 9-11 p.s.i. if it's port fuel then 48 p.s.i. You could have a bad MAF sensor as well I would start with these here are guides to help you.

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf

and

https://www.2carpros.com/articles/engine-has-low-power-output

Please run down these guides and report back

Cheers

I had the replace the MAF (mass air flow sensor) in my truck got one for $78.00 all fixed!

I've had this vehicle for about 1.5 years now and since I've got it I've rebuilt the transmission, had two tune-ups (and I am going to replace the spark plugs and wires this week), and of course changed to oil every 2,500-3,000 miles (I originally changed the oil over to Castrol Syntec 5W-30 but now I am only using Royal Purple 5W-30 oil). A couple of days ago, after taking only about a 30 mile highway trip (averaging about 82 MPH the whole way) I stopped at a red light after getting off the interstate, I hit the accelerator a little harder than normal since I was going up a hill and my engine seemed to sputter a little. I let off and hit the accelerator even harder and then it sputtered and shook and eventually died. I pulled into a parking lot and started it up again (with relative ease) and slowly hit the accelerator and there seemed to be no problem. I then put the car in neutral and basically put the pedal to the floor and it sputtered and died. I added Prestone Fuel System Cleaner to my gas and changed my oil that day to Royal Purple 5W-30 and a K&N Oil Filter. After doing this, I noticed that my engine seemed to run smoother (no noises under the hood that were there before), but there was clearly a noticeable loss of power and performance. I can now barely hear my exhaust as I hit the gas (I put a Flowmaster 40-series and a Random Technologies Cat on it a year ago so it's noticeably louder than a stock exhaust) and it seems to decelerate quicker and there is MUCH less low-end torque than I had before. I am seriously stumped at what the problem may be; please help.

does it have a check engine light on. One thing i would have checked is the fuel pressure.

The check engine light is not on. I replaced the fuel pressure regulator this past November.

[quote:cf0205b93a="rhall77"]does it have a check engine light on. One thing i would have checked is the fuel pressure.[/quote:cf0205b93a]

The check engine light is not on and I replaced the fuel pressure regulator last November

no check fuel pressure.

i have a 94 s10 v6 and about half the time i drive it, it runs fine, the other half any time i come to a stop or almost a stop it accelerates very very slow. once it picks up speed it runs a little better but still loses almost all acceleration after i stop, i have replaced fuel filter, spark plugs,wires,cap,button,and just today the knock sensors, the fuel pump and transmission tested fine and with this being my work truck im completely out of ideas

What was the fuel pressure spec?? Any applicable trouble codes? If you have the spider fuel system, the fuel poppets may need cleaning. Any testing needs to be done when the problem occurs. Yeah, intermittent issues can be tough.

after i changed the knock sensors and the catilic converter the change engine light when off and hasnt been back on and no codes are comming up but the problem is still occuring i forgot the fuel pressure spec but the diagnopstics read that it was fine. i thought it was the pump at first because in the morning to get it to idle right you have to give it some gas someone told me that it might be a torque converter. it feels like with a manual trans. when you are trying to go with the clutch not fully engadged. it wil still go but i could get out and walk faster than it picks up. thank you for any info you could give me

If the engine races while going slowly, I would have to suspect a transmission issue, of some kind.

i have a 94 chevy s-10 pickup it runs like it missing badly and my converter gets red hot i replaced the converter and coils and had ignition model check but still get red hot and has no power

Red hot means it's working, but being forced to work way too hard. It's not bad, . . . yet.

Pull the vacuum hose off the fuel pressure regulator and check for signs of raw fuel in it. If there is any wetness, replace the leaking regulator. GM has a ton of trouble with those.

caradiodo

Red hot means it is working, but being forced to work way too hard. It is not bad, . . . yet.

Pull the vacuum hose off the fuel pressure regulator and check for signs of raw fuel in it. If there is any wetness, replace the leaking regulator. GM has a ton of trouble with those.

caradiodoc

I have a single cam with a 4.3 Vortec that is half Jasper and half Vortec. I am trying to figure out where to start. My truck starts and runs fine at idle though it is a little rough coming out of the exhaust. But when I am driving down the road it loses power when the engine warms up. But when I floor it it seems fine then goes right back to being starved of fuel it seems like it it is getting too much. I am not sure but I can put it in neutral and it is fine and if I shift it manually down it runs fine.

Scan for codes and check fuel pressure with a gauge auto parts rent it. Do that first. See link.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Please help truck starts every time no problems yet runs rough at low rpm the gets smooth yet lacks power and when floored hesitates and starts to stall dont know how to set timming with a computer compression good new plugs wires and dis cap and rotor gas miliage real bad

It doesn't sound like a timing issue. Have you checked fuel pump pressure? Also, have you checked to make sure the catylatic converter isn't plugged?

Engine boggs down at about 2000 Rpm let off and idle down come back up to 2000RPM same thing Starts fine Idles fine

Hello
How many miles since the fuel filter was changed, if it has been a while start by replacing that and see if the problem goes away. It sounds like the filter may be plugged, if that doesn't help check the fuel pressure you may have a bad fuel pump.
john

My S-10 used to accelerate quite quickly, but for the last few months, it's been struggling to reach 60 in less than 15 seconds. It sat all winter, but all the fluids have been changed. I also changed the fuel filter, PCV valve, air filter is clean, and it just had a tune-up about 5,000 miles ago. There is the correct amount of air in the tires. I took it to the shop and they hooked it up to the diagnostic and found nothing wrong. Besides the acceleration problem, there seems to be nothing else wrong... except for horrible gas mileage. I used to get 26, now I'm down to 17. Yikes! Please help. Throw out any suggestions you think would work!! Thanks!!

Have the exhaust flow tested. Sounds like the converter or the muffler is partly plugged. Also check ALL the wiring to the sensors and engine, Sitting that long may have allowed a mouse or two to snack on the wiring.

The past couple of days I've read through everything here I could find and it gave me quite a bit of help but my blazer stills has a problem.

About 5 months ago I bought a 1994 S-10 Blazer with a 4.3L Vortec engine code W. It wouldn't start and after checking fuel pressure found out the fuel pump wasn't working. I went ahead and bought a new AC/Delco pump, pulsator, strainer, electrical connector w/pigtail, sending unit, dist. cap, rotor, plugs and wires, 2 fuel filters, changed engine oil and filter replaced the exhaust from the cat convertor back (old muffler and exhaust was rusted badly). Dropped the fuel tank and cleaned it out and installed the pump and sending unit. Put the tank back in the vehicle, installed one of the new fuel filters in the fuel line and put all the ignition stuff I bought in it. Put a fuel pressure gauge on it and made sure everything was working. I had fuel to the pressure gauge at the schrader valve so it seemed I was ready to fire it up. I tried that and it wouldn't start. I had hot blue spark but no fuel was getting to the plugs. I read in my manual that any problems found with the CMFI unit the entire assembly should be replaced. Well I was short on cash so I pulled the upper plenum and took the unit out, sprayed carb cleaner in the poppet valves and rusty nasty smelling fuel came out. Used some air (low) and blew everything dry and reinstalled it. Put on a new plenum gasket and bolted everything back together. After everything was bolted down and electrical connectors were back together I got in turned the key and within a few cranks of the engine it fired up. I let it warm up while I cleaned up the shop and took it for a drive. Everything was working fine. Drove it everyday to work for just over 4,000 miles then one day on the way home on the highway going up a hill I noticed I was losing power. Never did die but I had to step lightly on the peddle. Anymore than that and the engine rpm's fell. I made it home and when the weekend came I took it back out to the shop and decided to do some testing. Didn't know about this forum but I had the repair manual.....heck I can fix this myself...yeah right. I read in the manual that if the fuel pressure didn't approach 61lbs. on acceleration that the pressure regulator on the CMFI unit was bad and it should be replaced and this past weekend I replaced it. Well after reading through a ton of threads here I found out that its a good idea to replace the fuel line assembly (nut kit). I didn't do that and I really didn't look over the plenum to see if there was any wash. Well it's still doing the same thing it was doing. I put a fuel pressure gauge on the schrader valve and here is what I found out. With the key on/engine off and the fuel pump running I have 60lbs. as soon as the pump shuts off the pressure drops to 58lbs but within a couple seconds climbs back up to 60lbs. I turned the key off and let everything set for 10 minutes and the fuel pressure then was 58lbs. I started the engine and the pressure was between 51lbs. and 58lbs. (needle was fluttering back and forth). I increased the throttle to 2,000 rpm's and the pressure gauge needle flutters between 49 and 60lbs. Around 2500 rpm's and the engine starts to cut out, bog down or whatever. It won't throttle up anymore than that. It starts good and idles good and I can drive it in town but I can't take it out on the highway. I put a vacumn gauge on it and at idle it has 19 lbs/inches? and if I increase the throttle it increases to around 21 or 22 lbs/inches. I didn't pinch the return fuel line to see what would happen to the fuel pressure but I think I performed everything else. I'm really leaning towards replacing the fuel line assembly (nut kit) like I should have done when I replaced the CMFI unit. All the fuel pressure readings stay the same with the engine cold or when it's at operating temp. What do you guys think? Where should I go from here? Sure would appreciate any help you can give me. Sorry for the long winded post but I wanted you to know what all I've done.
Also wondering what would make the fuel pressure gauge needle flutter? Don't believe it's supposed to do that.

Hi
Well the gauge is going to move a little bit but did you check to see if you may have a bad trottle position sensor. Try this first and hopefuly this will help.