alright. as everyone knows rx7s and notorious for the hesitation. but mine isnt just at 3k like most cases. it can occur at every rpm. it is usually when on highway or something. doing a steady speed. the engine will basically misfire or hesitate. however you want to call it. better description is a studder. i cannot figure it out. please if any ideas of what to check or how to find out what it is please let me know

 

fuel pump sock because of rust

 

theres alot of things that can cause this.

replace fuel filter, check the injectors clips are plugged in , check if there is contact on your primary injector clips, check if the plugs are still good, check the airfilter, check the engine harness ground wiring, airflowmeter, tps..

 

i'm having the same problem, but only at 3k and it's bad enough to make you get whiplash

i'll have to go through all of those things to get to the bottom of it

the only thing i know about the car is that it's a rebuilt sp, rtek 1.7, rc engineering injectors and that's about it

 

yeah mine can cause whiplash too. also i think i have a bearing loose from my driveshaft to my diff so its nocking. i was thinking it may be because of that. but who knows. but my fuel filter has recently been replace. plugs. wires. grounds have been looked but not very much researched. i dont think its the fuel pump cuz my fuel pressure reads the exact same while the hesitation is occuring

 

I had the exact same problem... one second it ran beautifully and the next second I'd be thrown around... but mine was very strange... when I put in the clutch or left it in neutral, the engine rev'd up perfectly fine(most of the time).. maybe once or twice when I rev'd it I'd get multiple backfires... sounded like an uzi goin off. but I just bought a thing of Gumout, ran the thing rough(make sure you go above 3800 rpm to get the secondary injectors clean too) I just finished up the gas tank and my car's running amazingly well.. seriously felt like I got 20 hp back. it's only been a week so I don't know if it's perminantly better, but it's run beautifully with no hesitation since. so just clean the injectors and see. Good Luck

 

I am buying a car later this week and it runs fine but always at 3800 rpm it has a hesitation could this problem have the same solution as the ones given.

 

From the FAQ located at the top of threads.

"I have this hesitation whenever I accelerate right around 3500-4000 RPM
The dreaded 3800 RPM hesitation is cause 90% of the time by poor ground connections between the engine, the battery, and the car. Clean or replace all the under hood ground connections. On 86 model year cars , replacing/regrounding the pressure sensor's ground wire has helped (do not re-ground a 87 or later model year). If there is still a problem after that, look at cleaning the fuel injectors and (on a N/A) that your 5th/6th ports are operating correctly."

 

I had hesitation too. How did I fix it? Idk what one it is or a combo. But I stopped washing my car in a autowash and started using regular unleaded gas. The guy before me used only premium and then he drove the car after I started doing these. He said he had the hesitation for the whole time the engine was in it and he owned it. Idk if the non premium gas fixed it. But I don't have the hesitation at all anymore.

 

So i went and looked at the car and found out the guy already tried re-grounding it and replaced the TPS......any other ideas?

 

On 86 model year cars , replacing/regrounding the pressure sensor's ground wire has helped (do not re-ground a 87 or later model year)

Was this also included in his regrounding effort? And was the ECU also regrounded as well? Regrounding the battery and starter will help the electrical system but it won't help the 3800 rpm hesitation for the 1986 cars.