91 Celica GTS needing help diagnosing

[toyotadriftr]

Hey people.. So I've got a few issues with my 91 GTS 2.2L 5SFE Celica. I just recently rebuilt the entire engine. New pistons, rings, pumps, gaskets, everything. Even bored it out .020 (which I'm wondering if maybe this is the cause of my current problem) So now the car is running and seemingly well but the problem is that I have the idle all the turned way down and the car still idles 14-1600 RPM and then as I drive the faster I get (starting at 65/70 MPH) the RPM's drop and the engine cuts out just a bit then everything goes back to normal but it will do this repeatedly as I drive on the freeway. I'm afraid that it my cut out and die if I don't attend to the issue immediately.. Any suggestions on how to fix these issues would be greatly appreciated..

Thank you.

Jade
(toyotadriftR)

[fishexpo101]

A 0.020 overbore should be within the limits of the ECM pre-programmed map - I doubt that could the issue at hand, but it is possible that it is contributing to a larger problem. With it bored 0.020 over (~0.5mm) - it will still displace about 2.2L. If you bumped it 0.20 over (~5mm), now you have a 2.4L engine with stock ECM - then it would do exactly what you are mentioning here.

How long ago did you rebuild the engine? Did you rebuild the engine in the car or did you pull the engine? Did you put back all the sensors, verified the wiring? Check the obvious - timing, fuel , fire, components bolted back on correctly (intake and exhaust), etc.?

Some stuff that pops into mind after an engine swap or rebuild
- coolant temperature sensor, if it is messed up, will drive the car to a pretty high idle - also affect drivability at part throttle
- air in the block, coolant hadn't completely purged all the air in the block - an air bubble will cause problems that look like a ECT sensor problem
- big vacuum leak somewhere (most likely) - if a gasket curled up on you or shifted, could cause a vacuum leak. Vacuum leaks can cause all sorts of headaches.

[toyotadriftr]

I rebuilt it 3 months ago and I did pull the engine completely. I do believe that all the wiring and and sensors were replaced properly. I do need to upgrade all the sensors just so I have new ones in there. I also did go through and check the timing and set it using a timing light. The only problem I can think of with the exhaust bolts is that I had to helacoil a new bolt because the person that had the car before replaced the 2 way bolt backwards causing it to strip but that's all I can think of in that aspect.

I recently replace the O2 sensor because I was getting a code for it. Since I rebuilt the engine the idle has been high but it's only been in the last month that the engine cuts out while i'm driving. Could it be the O2 sensor?? I know that my car is a California model and requires a different type of O2 sensor. I am wondering if that could be the problem as well..? Do I not have the right type of sensor in it?

Thank you again for any help