dvourthis

I had a mechanic mentor that would say in a case like yours i got one tool to fix it: a hand grenade under the hood when no ones looking just my 2 cents. your problems seems quite convoluted. keep it simple and you cant go wrong.

deanshark

A hand grenade is only good if ya have insurance. This hesitation problem, which everyone has, is not something simple. There has to be more then one thing wrong connected to this problem. I had it and I unplugged my AFM and it runs awesome but very very rich.

Purevenom1

Still no update to give as I have not had a chance to look back into it yet. Trying to get done w/ a few more repairs before I start back on the Lexus. Seems like everytime I get ready to start back on it I get a few more in that needs to be done quick. So I geuss the Lexus is going to have to wait a little bit longer. Will update as soon as something else changes.

Dtwillis5

My brother have a nissan altima and his car started doing the same thing my car doing killing when given gas at 1700 rpms . Right now im doing a tune up, (its gon rain till Wednesday so thats when imma get back on it) four of the spark plugs was burn bad the other four was looking new. That says anything?

Purevenom1

I have installed new plugs and wires in it. Check the coils and they check out fine. The car runs great at idle and just slowly accelerating but when you press the gas to pass or get out in traffic the car stumbles . As long as you dont do that its fine. I would think if its a bad plug or something it would have the code for a misfire. As this is showing no codes on the dash except for when you check them. Also if you do the drive cycle w/ the jumper wires crossed it shows up. It has to be something real easy to fix just hard to locate.

deanshark

Hey Purevenom1, Just a thought but did you ever check your AFM? I know you're getting the code for the TPS but that might not even be the hesitation problem. When I had my hesitation I wasn't getting any codes but my AFM is bad. I took the advice from someone here (I think Och) and unplugged the AFM and it ran like a bear. The hesitation was gone and had some awesome power. I tested it and it's way out of spec but doesn't throw a code. It runs very rich with real ****ty MPG so I do need to change it, soon.

Purevenom1

Dean I have not. I will take a look at that in the next couple of days as I have 2 others that I need to finish up. Thanks for the info on it and I will see if that changes.

Dtwillis5

This could help
https://www.clublexus.com/forums/sho...d.php?t=551125

Purevenom1

Thanks for the link. Very interesting to say the least. Hopefully get a chance to get back on it. Trying to work through the other repairs since this one is a non paying one. lol

firefly

any update to this?

amm5172

I have 2 1st Gen's with this exact same problem. A 93 with 106k and a 94 with 144k. I fought this problem for months replacing everything from AFM, TPS, plugs, wires, caps, rotors, injectors, etc. When it was all said and done a $100.00 ECM from the junkyard fixed the problem in both cars. I am pretty handy with a soldering iron and replaced all of the electrolytic caps in both ECM's to no avail. The problem is definitely in the ECM although I haven't actually isolated the exact problem. If I had an oscilloscope it would be a lot easier. I have noticed that in all of the threads I have read, and of the 5 First Gen's I have had, this problem seems to be isolated to the 93 and 94 models.

firefly

How was the board where the caps leaked?

amm5172

Oily but not corroded. Easily cleanable with a flux removal pen. I think the problem lies in weak diode or bad power mosfet. What finally convinced me it was the ECM was that while monitoring on a Snapon Athos at around 1700 - 1900 RPM the Athos would lose signal from the ECM. It act's like the ECM is losing power for a second under a load.

fluxedup

Not to hijack , but man , what your descibeing with losing signal from the ecm at that rpm range sounds like my 94. A really jerky stutter that is so stacatto. Friends have said fuel pump , but I have never experienced a jolt like this from a fuel pulsing issue.It happens on a fairly random ( it seems anyway)basis Also, I imagine an ecm issue like this would result as more a function of time/age rather than mileage. Here in Phx the heat kills everything the sunlight does not. But, it is a dry heat....hahahabwaahaha......

Bott63

Any updates? I have a VERY slight hesitation, so I'm staying tuned in...

One suggestion that I'm contemplating... Fuel injectors? These things DON'T last forever... Especially something to consider if they are OEM original to the car. I had very similar issues with a German Car. Replaced several components with new, and swapped damn near everything else with used from perfectly good running cars to no avail... Last thing I did, was swap out injectors with new. The 25 year old, 135k mile car ran like it was brand new!

It looks like we can still get new injectors for less than $160 for a set of 8. To have them overhauled and bench flowed costs about $20 each, so new is the way to go for this application...