I'm noticing a flat spot in acceleration at about 2k rpm. Before and after (higher and lower rpm) it pulls good. Mainly during light throttle, it acts almost like I'm holding the throttle steady for a second at about 2k rpm, even though I'm still mashing down on the gas slowly. Its a 98, auto, 360, 152k miles. Now I've done some work to the truck recently, some in an attempt to find the problem. Cap, rotor, plugs, and wires changed recently. Fresh plenum, 02, tps. Swapped in another map sensor (not new), but noticed no change. I really didn't notice it until after my new exhaust, but I'm not sure if I didn't notice it because the factory exhaust was so quiet and I couldn't hear what the engine was doing, or if I've lost some low end pwr from the exhaust itself. Shouldn't have affected low end I wouldn't think..its a 3" single custom cat back into a magnaflow, stock pipe routing. Maybe these motors naturally come alive a little past 2k rpm and I didn't notice it as much before I could hear the exhaust. Also, I'm running the factory fuel pump and I have considered that it could be going out, but the only other time I had a fuel pump fail (in a chevy), it would totally stop pumping sporadically. Was much more pronounced and noticeable. Anyone have any input? Not a huge problem, but the little stuff always seems to be the hardest to diagnose.

 

sounds like a tps... but you said you have a new one what kind did you get?

 

does it do it cold or hot .the coolant temp sensor can throw a few curve ***** at the fuel system if its not reading correct engine temp.you can also check your tps with an ohm/voltmeter for dead spots .

 

Got it from the dealership. And it cost too much. Got a 100 dollar safety bonus at work, sensor pretty much took that.

 

Have noticed it more when at running temp. May be because I live on backroads and can't really accelerate much until I get to the highway, and by that time truck is at operating temp. Will have to try and notice if it does it cold. I'm kinda thinking it doesn't. Coolant temp sensor is the one near the t-stat on manifold, right?

 

What kind of air hat intake are you running? might not be flowing enough for the new exhaust. you could try a cheap 14X3" round setup or even a K&N filter to see if it gets over the hump. An aftermarket SCT tuner would no doubt help as well.

 

What gear is this happening in....are you trying to pass cars or getting on highway, my truck when in the wrong gear used to kinda sit at 2k for a little until it either downshifted or slowly started climbing rpms

 

this is exactly what I was thinking too.. there is a natural lull there on my truck to- mine is actually about 1900 RPM.. it's the same area where the TC locks after OD.. it takes a little 'punch' to get out of it after it's settled in there while driving steady speeds..

if I'm running 55+ it doesn't happen, as the RPM's are somewhere around 2.1k~2.2k... if I'm cruising through town though, that's precisely what and where mine does the same thing..

 

Stock air hat, stock filter. Have a spectre drop-in that I could try. Had thought about trying it again now that its winter and has rained again. I worry about how the filter fine dust. Where I work is duuusty, dude. Sct, yep, have been seriously considering that, actually requested info on it in another post.

 

Notice it most in 3rd. If I'm in 3rd gear, accelerating slow and steady. Have never looked at a hp/tq curve on these motors. Is there a hp spike at 2k rpm? I'm almost thinking the louder exhaust is letting me hear what the motor's always been doing, just hearing it makes it more noticeable.