Truck has always felt limited after 3000 rpm. Crank sensor?

Well after 30,000 miles from 192,000 to 222,000 I have always struggled to get the truck over 3000 RPM. I mean it runs fine it’s towed fine but you’ve got a shift at 3000 RPM. It being my second vehicle, I always just sort of live with it, but wondered. Anyway, I’m pressing it into more service. It’s only been getting 3500 miles a year probably gonna start putting more like seven or 8000 miles a year on it. It’s going in for new exhaust system as I’m getting the P0171 code and I know I’ve got exhaust leaks. Using the incardoc app recently led me to noticing wild fluctuations on the timing advance. Leading to an aha moment that I probably had a cam sensor or a crankshaft sensor problem, and that this may be the root of all the trouble with the rev limiter feeling. After a quick search of the Internet, it appears as if this is one of those sleeper problems, often not throwing any codes. Going to order a crankshaft sensor to have on hand when I pull the old one out. I’ve found some ohm readings to look for so hopefully it’s just gonna be obviously bad and I’ll throw the new one in. Really hoping that suddenly the truck will go to 5000 RPM! if anyone has experience with this feel free to chime in. I’ll post back here if the truck suddenly starts running like I’ve always thought it should. I’m gonna definitely feel like an idiot if this fixes the problem.

 

P0171 is typically not associated with an exhaust leak. 171 is associated with an engine vacuum leak from the maf and after, vacuum lines

 

P0171 also appears when fuel delivery is limited, there are no codes for fuel pump so if its running lean you need to investigate many things.

Look at ST and LT Fuel trim, don't look at timing, its supposed to swing around rapidly. This is 100% not a crank sensor.

 

I feel like I have a similar symptom where I never accelerate past 3000 rpm. The engine starts to sound a bit stressed and choppy. Curious to see if you resolve that issue.

 

Lots of places to start…..

 

Just spent $1,550 for a completely new exhaust system. The sensor before the CAT was hanging by it’s wires. The CAT had a hole in it. All flanges were leaking. The muffler was shot and the tailpipe was paper thin in spots. When I bought it in 2015 I figured I’d get 5 more years out of the exhaust. I got 8. It sounds better! We’ll see if the P0171 code stays off. The custom muffler shop reused my two existing oxygen sensors. I had a pair of new Denso sensors in the cab for them if they needed them. So I got my money back for those. Also got a 5 year warranty on the new parts.

The mechanic next door to the muffler shop is a first gen enthusiast and owns a 2004! He’s looking at my crankshaft sensor on Thursday plus a couple other random things. Until today I was the only person wrenching this since 2015. But, my back is currently messed up and I have no garage and it’s cold. So, my wallet is open. If the Crank sensor fixes the rev limitation problem I’ll be thrilled. Had to deal with the exhaust first! Fingers crossed.

 

Keep us posted. Definitely interested to see what happens.

 

I had this same issue. It was like I was hitting the rev limiter but it was happening at ~3500 RPMs. Replaced the crank sensor with a Denso brand one from RockAuto. Immediate night and day difference. Now I can bouce off the real rev limiter at 5500 if I choose.

The one in there is 25 years old. If you have a new crank sensor on hand, install it. They aren't very expensive and really easy to swap out.

 

Well, I finally got around to putting the DENSO crankshaft sensor in. Pulled my usual rpm’s in 1st and second gear somewhere around 2500ish but then 3rd gear rolled up to 3000 and kept going to 3500 no problem. Hit 4th gear and ripped up to 4000 rpm for the first time ever since getting the truck in 2015. I did another run pulling up to 4000 rpm in both 3rd and 4th. Going to get on the highway with it next week and see what 5th gear feels like. I wouldn’t regularly be pushing it to 4000 rpm but I’m pretty happy that I can now exceed 3000 rpm and even that 2800 rpm is so much more comfortable. I’m going to have to relearn my third and 4th gear shifting. Anyway, the thing never threw a code. Just always stumbled at 3000 rpm and would not push beyond 3200 at all. Always had enough power and even towed with it like that. This is so much better.