When I'm driving in 5th gear on the hi-way and drop my speed down below 60mph my car starts to jerk like I'm in a gear to hi for that speed. If I speed up past 60 it smooths back out. I know this shouldn't happen but I haven't been able to figure it out. It also does this in other gears as well. I know I should be able to drive in 5th gear at 60 without it jerking. Any suggestions.

I have a WC T-5 w/ 355 with .510 lift cam.

Let me know what you think.

 

Sounds like an ignition problem...

 

Ignition problem?? How so? Can you explain a little more on why you think this??

 

Anymore suggestions??

 

Check for a burnt spark plug wire or boot. That may be your problem.

 

Everything has been checked no burnt spark plug wires. My the guy who setup my car seems to think it's the cam. I'm not so sure.....

 

i was going to suggest downshifting and seeing if that eliminated the problem, but you said you tryed that, right?

 

Yeah that works but why should I have to dwn shift from 5th gear going only 60mph???

 

Put a 4:88 rear end gear in it and the high rpms will fix ya right up!!
Seriously, I would check the fuel pump.. when a motor is "lugging" as it is in high gear it will definately do what you discribe, the higher RPMs (as in a lower gear) puts a lot less 'requirment' on the fuel pump pressure.
Good luck!

 

My guess would be fuel pump too. Surging at high speeds or heavy acceleration is most likely a poor fuel supply. Have you changed the fuel filter lately/ While at it put a guage on the fuel line and see if it is within specs

 

I have a new fuel pump as well.....

 

yeah I had a fuelpumpthat was defective too it pumped in 2 and half gallons of gas into the crankcase. Check the fuel pressure at cruising speed and get on it a little bit and check if the pressure drops. Its worth checking

 

Yeah I'll do that too...but everything seemed okay when I had the fuel pump installed. My fuel pressure shot up from 48psi to 60+psi....Keep the ideas coming

 

What is the FP now?? 60PSI???

 

not really up on FI but 60psi sounds like alot. I could be wrong too much fuel will cuase a bog too are plugs reading rich or lean

 

No....Its at 43psi right now....sorry to get you alarmed but thanks for looking out.

 

Any more ideas/suggestions??

 

Check for slack in your drivetrain, when the converter locks on my car, at low rpm, it will do that. Something about not having enough consistent power to the wheels will make it jerk a bit at low rpm. just a thought...

 

The slack in the drivetrain??? What specificially??

 

Well I've check everything that I can and it still jerks...any further suggestions??

 

This just came to me replace the lockup solenoid on the transmission. The tranny locking and locking of the solenoid would cause the problem you described. It is a 700r4 right?

 

No it's a T-5

 

I've heard of the fuel supply doing this before....I use to have an 84 firebird (with the 5 speed, not that it mattered) that did this, and it turned out to be the EGR valve was bad....Not sure if you have one on your car, but that's what caused it on this car.....
just giving suggestions.....thanks

 

Yeah I thought about that too but I'm not getting any trouble codes....everything is checking out fine but I know it can't be because I'm still having this problem.